It was reported by some of you that you cannot edit the posts posted by you.here is a tutorial i found on the web that might help you guys solve the problem.
http://www.google.com/support/blogger/bin/answer.py?hl=en&answer=41382
If anyone has any problems with the posting,contact me at 9712 8509 or wcms_ichigoms@hotmail.com
WC.Xene
---------------------------------------------------------------------------
Electric current
Main article: Electric current
The movement of electric charge is known as an electric current, the intensity of which is usually measured in amperes. Current can consist of any moving charged particles; most commonly these are electrons, but any charge in motion constitutes a current.
By historical convention, a positive current is defined as having the same direction of flow as any positive charge it contains, or to flow from the most positive part of a circuit to the most negative part. Current defined in this manner is called conventional current. The motion of negatively-charged electrons around an electric circuit, one of the most familiar forms of current, is thus deemed positive in the opposite direction to that of the electrons.[26] However, depending on the conditions, an electric current can consist of a flow of charged particles in either direction, or even in both directions at once. The positive-to-negative convention is widely used to simplify this situation.
An electric arc provides an energetic demonstration of electric currentThe process by which electric current passes through a material is termed electrical conduction, and its nature varies with that of the charged particles and the material through which they are travelling. Examples of electric currents include metallic conduction, where electrons flow through a conductor such as metal, and electrolysis, where ions (charged atoms) flow through liquids. While the particles themselves can move quite slowly, sometimes with an average drift velocity only fractions of a millimetre per second,[16] the electric field that drives them itself propagates at close to the speed of light, enabling electrical signals to pass rapidly along wires.[27]
Current causes several observable effects, which historically were the means of recognising its presence. That water could be decomposed by the current from a voltaic pile was discovered by Nicholson and Carlisle in 1800, a process now known as electrolysis. Their work was greatly expanded upon by Michael Faraday in 1833.[28] Current through a resistance causes localised heating, an effect James Prescott Joule studied mathematically in 1840.[28] One of the most important discoveries relating to current was made accidentally by Hans Christian Ørsted in 1820, when, while preparing a lecture, he witnessed the current in a wire disturbing the needle of a magnetic compass.[29] He had discovered electromagnetism, a fundamental interaction between electricity and magnetics.
In engineering or household applications, current is often described as being either direct current (DC) or alternating current (AC). These terms refer to how the current varies in time. Direct current, as produced by example from a battery and required by most electronic devices, is a unidirectional flow from the positive part of a circuit to the negative.[30] If, as is most common, this flow is carried by electrons, they will be travelling in the opposite direction. Alternating current is any current that reverses direction repeatedly; almost always this takes the form of a sinusoidal wave.[31] Alternating current thus pulses back and forth within a conductor without the charge moving any net distance over time. The time-averaged value of an alternating current is zero, but it delivers energy in first one direction, and then the reverse. Alternating current is affected by electrical properties that are not observed under steady state direct current, such as inductance and capacitance.[32] These properties however can become important when circuitry is subjected to transients, such as when first energised.
Benjamin Ong
Main article: Electric current
The movement of electric charge is known as an electric current, the intensity of which is usually measured in amperes. Current can consist of any moving charged particles; most commonly these are electrons, but any charge in motion constitutes a current.
By historical convention, a positive current is defined as having the same direction of flow as any positive charge it contains, or to flow from the most positive part of a circuit to the most negative part. Current defined in this manner is called conventional current. The motion of negatively-charged electrons around an electric circuit, one of the most familiar forms of current, is thus deemed positive in the opposite direction to that of the electrons.[26] However, depending on the conditions, an electric current can consist of a flow of charged particles in either direction, or even in both directions at once. The positive-to-negative convention is widely used to simplify this situation.
An electric arc provides an energetic demonstration of electric currentThe process by which electric current passes through a material is termed electrical conduction, and its nature varies with that of the charged particles and the material through which they are travelling. Examples of electric currents include metallic conduction, where electrons flow through a conductor such as metal, and electrolysis, where ions (charged atoms) flow through liquids. While the particles themselves can move quite slowly, sometimes with an average drift velocity only fractions of a millimetre per second,[16] the electric field that drives them itself propagates at close to the speed of light, enabling electrical signals to pass rapidly along wires.[27]
Current causes several observable effects, which historically were the means of recognising its presence. That water could be decomposed by the current from a voltaic pile was discovered by Nicholson and Carlisle in 1800, a process now known as electrolysis. Their work was greatly expanded upon by Michael Faraday in 1833.[28] Current through a resistance causes localised heating, an effect James Prescott Joule studied mathematically in 1840.[28] One of the most important discoveries relating to current was made accidentally by Hans Christian Ørsted in 1820, when, while preparing a lecture, he witnessed the current in a wire disturbing the needle of a magnetic compass.[29] He had discovered electromagnetism, a fundamental interaction between electricity and magnetics.
In engineering or household applications, current is often described as being either direct current (DC) or alternating current (AC). These terms refer to how the current varies in time. Direct current, as produced by example from a battery and required by most electronic devices, is a unidirectional flow from the positive part of a circuit to the negative.[30] If, as is most common, this flow is carried by electrons, they will be travelling in the opposite direction. Alternating current is any current that reverses direction repeatedly; almost always this takes the form of a sinusoidal wave.[31] Alternating current thus pulses back and forth within a conductor without the charge moving any net distance over time. The time-averaged value of an alternating current is zero, but it delivers energy in first one direction, and then the reverse. Alternating current is affected by electrical properties that are not observed under steady state direct current, such as inductance and capacitance.[32] These properties however can become important when circuitry is subjected to transients, such as when first energised.
Benjamin Ong
Category:
0
comments
Hola hola! buon giorno a tutti!
This video introduces the concept of an electric circuit. It describes the difference between an open and closed circuit.
___________________________________________________
___________________________________________________
Nieh! OK, an electric circuit is an interconnection of electric components such that electric charge is made to flow along a closed path (a circuit), usually to perform some useful task.
The components in an electric circuit can take many forms, which can include elements such as resistors, capacitors, switches, transformers and electronics. Electronic circuits contain active components, usually semiconductors, and typically exhibit non-linear behaviour, requiring complex analysis. The simplest electric components are those that are termed passive and linear: while they may temporarily store energy, they contain no sources of it, and exhibit linear responses to stimuli.
That is all we have time for.
Done by Ryan,2E3
ps:/pariah is a jerk/
-federiksen forever-
This video introduces the concept of an electric circuit. It describes the difference between an open and closed circuit.
___________________________________________________
___________________________________________________
Nieh! OK, an electric circuit is an interconnection of electric components such that electric charge is made to flow along a closed path (a circuit), usually to perform some useful task.
The components in an electric circuit can take many forms, which can include elements such as resistors, capacitors, switches, transformers and electronics. Electronic circuits contain active components, usually semiconductors, and typically exhibit non-linear behaviour, requiring complex analysis. The simplest electric components are those that are termed passive and linear: while they may temporarily store energy, they contain no sources of it, and exhibit linear responses to stimuli.
That is all we have time for.
Done by Ryan,2E3
ps:/pariah is a jerk/
-federiksen forever-
Category:
0
comments
As everybody knows electricity is one of the most needed stuff we need in daily life, we can't afford to not having it.It allows our television,computer,washing machine and refrigerator to work. Abuses of electricity often result in fire, so must handle it in care.If you burn a material like paper using electricity with high voltage,it will sure burn it.Have you ever tried to heat a fruit with electricity(high voltage)? Below is a video on electricity.
There is also another video about electricity, but this time it relates to battery. As everybody know,there must be battery so that a circuit will set up. But do you think lemon can replace battery as "battery"? The following video will review your answer.
The aim of this experiment is to show students how batteries work. After the battery is assembled, a multimeter can be used to check the generated voltage. In order for a more visible effect to be produced, a few lemon cells connected in series can be used to power a standard LED. Flashlight bulbs are generally not used because the lemon battery cannot produce the amount of current required to light such bulbs. Digital clocks can work well, and some toymakers offer small kits with a clock that can be powered by two potatoes or lemons.
The energy for the battery does not come from the lemon or potato, but rather the energy comes from the chemical change in the zinc. The zinc is oxidized inside the lemon, exchanging some of its electrons in order to reach a lower energy state, and the energy released provides the power. The lemon or potato merely provides an environment where this can happen, but they are not used up in the process.
Creating a battery from a lemon is a common project in many science text books. Successfully creating one of these devices is not easy.
Batteries consist of two different metals suspended in an acidic solution. Copper and Zinc work well as the metals and the citric acid content of a lemon will provide the acidic solution.
Batteries like this will not be able to run a motor or energize most light bulbs. It is possible to produce a dim glow from an LED.
The picture at the top of this page shows a basic lemon battery, a lemon, copper penny and zinc coated nail.
The lemon: A large, fresh, "juicy" lemon works best.
The nail: Galvanized nails are coated in zinc. I used a 2" galvanized common nail.
The penny: Any copper coin will work. (Canadian pennies from 1960 - 2001 all worked)
Creating the battery: Insert a penny into a cut on one side of the lemon. Push a galvanized nail into the other side of the lemon. The nail and penny must not touch
.
This is a single cell of a battery. The zinc nail and the copper penny are called electrodes. The lemon juice is called electrolyte.
All batteries have a "+" and "-" terminal. Electric current is a flow of atomic particles called electrons. Certain materials, called conductors, allow electrons to flow through them. Most metals (copper, iron) are good conductors of electricity. Electrons will flow from the "-" electrode of a battery, through a conductor, towards the "+" electrode of a battery. Volts (voltage) is a measure of the force moving the electrons. (High voltage is dangerous!)
I have connected a volt meter to our single cell lemon battery. The meter tells us this lemon battery is creating a voltage of 0.906 volts.
Unfortunately this battery will not produce enough current (flowing electrons) to light a bulb.
To solve this problem we can combine battery cells to create higher voltages. Building more lemon batteries and connecting them with a metal wire from "+" to "-" adds the voltage from each cell.
The two lemon batteries above combine to produce a voltage of 1.788 volts. This combination still does not create enough current to light a small bulb. Note the red wire connecting the batteries is joined from "+" (penny) to "-" (galvanized nail).
Four lemon batteries create a voltage of 3.50 volts. We should be able to light up a small device like an LED (Light Emitting Diode).
Note the connecting wires go from "+" to "-" on each battery.
LED
To turn on an LED you must determine the "+" and "-" connections. If you look closely at the red plastic base of an LED you will notice a "flat" spot (indicated by arrow above). The wire that comes out beside the flat spot must connect to the "-" side of a battery, the other wire to the "+" side.
Important information about LEDs: LEDs are designed to work at very low voltages (~ 2V) and low currents. They will be damaged if connected to batteries rated at over 2 volts. LEDs require resistors to control current when used with batteries rated at over 2 volts. Lemon batteries produce low current. It is OK to connect an LED to a lemon battery.
In the above image, electrons flow from the "-" (nail) end of our lemon battery through the LED (making it glow) then back to the "+" (penny) end of the battery. This is an electronic circuit. The LED glows dimly with this configuration.
Improving your battery.
The quality of the copper and zinc can be a problem for a battery like this. Pennies in particular are rarely pure copper.
Try substituting a length of 14 gauge copper wire (common house wire) for the penny. Experiment with different lengths and configurations of electrodes. Other sources of zinc and copper may be found in the plumbing supply department of a hardware store.
LIM WEI BIN(26) 2E3
____________________________________________________________________
There is also another video about electricity, but this time it relates to battery. As everybody know,there must be battery so that a circuit will set up. But do you think lemon can replace battery as "battery"? The following video will review your answer.
The aim of this experiment is to show students how batteries work. After the battery is assembled, a multimeter can be used to check the generated voltage. In order for a more visible effect to be produced, a few lemon cells connected in series can be used to power a standard LED. Flashlight bulbs are generally not used because the lemon battery cannot produce the amount of current required to light such bulbs. Digital clocks can work well, and some toymakers offer small kits with a clock that can be powered by two potatoes or lemons.
The energy for the battery does not come from the lemon or potato, but rather the energy comes from the chemical change in the zinc. The zinc is oxidized inside the lemon, exchanging some of its electrons in order to reach a lower energy state, and the energy released provides the power. The lemon or potato merely provides an environment where this can happen, but they are not used up in the process.
Creating a battery from a lemon is a common project in many science text books. Successfully creating one of these devices is not easy.
Batteries consist of two different metals suspended in an acidic solution. Copper and Zinc work well as the metals and the citric acid content of a lemon will provide the acidic solution.
Batteries like this will not be able to run a motor or energize most light bulbs. It is possible to produce a dim glow from an LED.
The picture at the top of this page shows a basic lemon battery, a lemon, copper penny and zinc coated nail.
The lemon: A large, fresh, "juicy" lemon works best.
The nail: Galvanized nails are coated in zinc. I used a 2" galvanized common nail.
The penny: Any copper coin will work. (Canadian pennies from 1960 - 2001 all worked)
Creating the battery: Insert a penny into a cut on one side of the lemon. Push a galvanized nail into the other side of the lemon. The nail and penny must not touch
.
This is a single cell of a battery. The zinc nail and the copper penny are called electrodes. The lemon juice is called electrolyte.
All batteries have a "+" and "-" terminal. Electric current is a flow of atomic particles called electrons. Certain materials, called conductors, allow electrons to flow through them. Most metals (copper, iron) are good conductors of electricity. Electrons will flow from the "-" electrode of a battery, through a conductor, towards the "+" electrode of a battery. Volts (voltage) is a measure of the force moving the electrons. (High voltage is dangerous!)
I have connected a volt meter to our single cell lemon battery. The meter tells us this lemon battery is creating a voltage of 0.906 volts.
Unfortunately this battery will not produce enough current (flowing electrons) to light a bulb.
To solve this problem we can combine battery cells to create higher voltages. Building more lemon batteries and connecting them with a metal wire from "+" to "-" adds the voltage from each cell.
The two lemon batteries above combine to produce a voltage of 1.788 volts. This combination still does not create enough current to light a small bulb. Note the red wire connecting the batteries is joined from "+" (penny) to "-" (galvanized nail).
Four lemon batteries create a voltage of 3.50 volts. We should be able to light up a small device like an LED (Light Emitting Diode).
Note the connecting wires go from "+" to "-" on each battery.
LED
To turn on an LED you must determine the "+" and "-" connections. If you look closely at the red plastic base of an LED you will notice a "flat" spot (indicated by arrow above). The wire that comes out beside the flat spot must connect to the "-" side of a battery, the other wire to the "+" side.
Important information about LEDs: LEDs are designed to work at very low voltages (~ 2V) and low currents. They will be damaged if connected to batteries rated at over 2 volts. LEDs require resistors to control current when used with batteries rated at over 2 volts. Lemon batteries produce low current. It is OK to connect an LED to a lemon battery.
In the above image, electrons flow from the "-" (nail) end of our lemon battery through the LED (making it glow) then back to the "+" (penny) end of the battery. This is an electronic circuit. The LED glows dimly with this configuration.
Improving your battery.
The quality of the copper and zinc can be a problem for a battery like this. Pennies in particular are rarely pure copper.
Try substituting a length of 14 gauge copper wire (common house wire) for the penny. Experiment with different lengths and configurations of electrodes. Other sources of zinc and copper may be found in the plumbing supply department of a hardware store.
LIM WEI BIN(26) 2E3
____________________________________________________________________
Category:
0
comments
Electricity figures everywhere in our lives. Electricity lights up our homes, cooks our food, powers our computers, television sets, and other electronic devices. Electricity from batteries keeps our cars running and makes our flashlights shine in the dark.
But what is electricity? Where does it come from? How does it work? Before we understand all that, we need to know a little bit about atoms and their structure.
All matter is made up of atoms, and atoms are made up of smaller particles. The three main particles making up an atom are the proton, the neutron and the electron.
Electrons spin around the center, or nucleus, of atoms, in the same way the moon spins around the earth. The nucleus is made up of neutrons and protons.
Electrons contain a negative charge, protons a positive charge. Neutrons are neutral -- they have neither a positive nor a negative charge.
Each atom has a specific number of electrons, protons and neutrons. But no matter how many particles an atom has, the number of electrons usually needs to be the same as the number of protons. If the numbers are the same, the atom is called balanced, and it is very stable.
Some kinds of atoms have loosely attached electrons. An atom that loses electrons has more protons than electrons and is positively charged. An atom that gains electrons has more negative particles and is negatively charge. A "charged" atom is called an "ion."
Electrons can be made to move from one atom to another. When those electrons move between the atoms, a current of electricity is created. The electrons move from one atom to another in a "flow." One electron is attached and another electron is lost.
That is how an electrical current is formed.
Daniel
_____________________________________________________________________
But what is electricity? Where does it come from? How does it work? Before we understand all that, we need to know a little bit about atoms and their structure.
All matter is made up of atoms, and atoms are made up of smaller particles. The three main particles making up an atom are the proton, the neutron and the electron.
Electrons spin around the center, or nucleus, of atoms, in the same way the moon spins around the earth. The nucleus is made up of neutrons and protons.
Electrons contain a negative charge, protons a positive charge. Neutrons are neutral -- they have neither a positive nor a negative charge.
Each atom has a specific number of electrons, protons and neutrons. But no matter how many particles an atom has, the number of electrons usually needs to be the same as the number of protons. If the numbers are the same, the atom is called balanced, and it is very stable.
Some kinds of atoms have loosely attached electrons. An atom that loses electrons has more protons than electrons and is positively charged. An atom that gains electrons has more negative particles and is negatively charge. A "charged" atom is called an "ion."
Electrons can be made to move from one atom to another. When those electrons move between the atoms, a current of electricity is created. The electrons move from one atom to another in a "flow." One electron is attached and another electron is lost.
That is how an electrical current is formed.
Daniel
_____________________________________________________________________
Category:
0
comments
It due to lights that reflects off of the retinas in our eyes.In many animals,including dogs,cats and deer,the retina has a special reflective layer called the tapetum lucidum that acts almost like a mirror at the backs of their eyes.If you shine a flashlight into their eyes at night, their eye shine back with bright,white light.Which is due to tapetum lucidum,among many nocturnal vertebrates the white compound guanine is found in the retina of the eye.Provide a mirrorlike surface, the tapetum lucidum,which reflects light outward and allows a second chance for its absorption by visual pigments at very low intensities.But human,don't have tapetum lucidum layer in their retinas.But cause by a reflection off of the retina which you see is the red colour from the blood vessels nourishing the eye.
Lim Qin Ping(2e3)
Lim Qin Ping(2e3)
Category:
Scieb=n
0
comments
Notes:
Refraction of light which is bending of light,occurs when the light passes through a medium that is of different density.
When the light pass through a denser medium from a less medium,the light ray will bend towards the normal.
When the light moving from a denser medium to a less dense medium,it will bend towards the medium.
Look at the following Example:
Refraction of Light
(That was totally drawn by me !)(Textbook pg 23.)
Here's a video about cool tricks refraction can do.The link's below:
http://www.youtube.com/watch?v=DtDaQPbKV9s&feature=related
Thank You ! Bye!
Totally 100% Done By Soh Wei Quan 2E3
E.Mail>>>sohweiquan@live.com(Dont spam PLS!)
Refraction of light which is bending of light,occurs when the light passes through a medium that is of different density.
When the light pass through a denser medium from a less medium,the light ray will bend towards the normal.
When the light moving from a denser medium to a less dense medium,it will bend towards the medium.
Look at the following Example:
Refraction of Light
(That was totally drawn by me !)(Textbook pg 23.)
Here's a video about cool tricks refraction can do.The link's below:
http://www.youtube.com/watch?v=DtDaQPbKV9s&feature=related
Thank You ! Bye!
Totally 100% Done By Soh Wei Quan 2E3
E.Mail>>>sohweiquan@live.com(Dont spam PLS!)
Category:
0
comments
The law of conversation of energy states that energy can change from one form to another, but cannot be created or destroyed.
naim
_____________________________________________________________________________________
naim
_____________________________________________________________________________________
Category:
0
comments
Light is simply a name for a range of electromagnetic radiation that can be detected by the human eye.
Electromagnetic radiation has a dual nature as both particles and waves. One way to look at it is as changing electric and magnetic fields which propagate through space, forming an electromagnetic wave. This wave has amplitude, which is the brightness of the light, wavelength, which is the color of the light, and an angle at which it is vibrating. In terms of the modern quantum theory, electromagnetic radiation consists of particles called photons, which are packets ("quanta") of energy which move at the speed of light. In this particle view of light, the brightness of the light is the number of photons, the color of the light is the energy contained in each photon.
Gene
--------------------------------------------------------------------------------------------
Electromagnetic radiation has a dual nature as both particles and waves. One way to look at it is as changing electric and magnetic fields which propagate through space, forming an electromagnetic wave. This wave has amplitude, which is the brightness of the light, wavelength, which is the color of the light, and an angle at which it is vibrating. In terms of the modern quantum theory, electromagnetic radiation consists of particles called photons, which are packets ("quanta") of energy which move at the speed of light. In this particle view of light, the brightness of the light is the number of photons, the color of the light is the energy contained in each photon.
Gene
--------------------------------------------------------------------------------------------
Category:
0
comments
Electric eel
Thiseel can give up to 800 watts of electricity everytime it moves. two atuminium panels inside the freshwater tank act as electrodes.
The electric eel has three abdominal pairs of organs that produce electricity: the Main organ, the Hunter's organ, and the Sachs organ. These organs comprise four-fifths of its body, and are what give the electric eel the ability to generate two types of electric organ discharges,low voltage and high voltage.The electric eel generates its characteristic electrical pulse in a manner similar to a battery, in which stacked plates produce an electrical charge. In the electric eel, some 5,000 to 6,000 stacked electroplaques are capable of producing a shock at up to 500 volts and 1 ampere of current (500 watts). Such a shock could be deadly for an adult human.
By Yong Wei
_________________________________________________________________________________
Thiseel can give up to 800 watts of electricity everytime it moves. two atuminium panels inside the freshwater tank act as electrodes.
The electric eel has three abdominal pairs of organs that produce electricity: the Main organ, the Hunter's organ, and the Sachs organ. These organs comprise four-fifths of its body, and are what give the electric eel the ability to generate two types of electric organ discharges,low voltage and high voltage.The electric eel generates its characteristic electrical pulse in a manner similar to a battery, in which stacked plates produce an electrical charge. In the electric eel, some 5,000 to 6,000 stacked electroplaques are capable of producing a shock at up to 500 volts and 1 ampere of current (500 watts). Such a shock could be deadly for an adult human.
By Yong Wei
_________________________________________________________________________________
Category:
0
comments
Hi . Joash here(:
Electricity . Isn't it such a wonderful thing? It helps us in out daily life A LOT . Well, electricity is a general term that encompasses a variety of phenomena resulting from the presence and flow of electric charge . These include many easily recognizable phenomena, such as lightning and static electricity, but in addition, less familiar concepts, such as the electromagnetic field and electromagnetic induction .
*Video removed due to irrelevant content.*
-Joash
______________________________________________________________________________________
Electricity . Isn't it such a wonderful thing? It helps us in out daily life A LOT . Well, electricity is a general term that encompasses a variety of phenomena resulting from the presence and flow of electric charge . These include many easily recognizable phenomena, such as lightning and static electricity, but in addition, less familiar concepts, such as the electromagnetic field and electromagnetic induction .
*Video removed due to irrelevant content.*
-Joash
______________________________________________________________________________________
Category:
0
comments
LIGHTNING
this article that i am posting is about lightning, an atmospheric electrical phenomenon.
what is lightning?
Lightning is an atmospheric discharge of electricity that is usually accompanied by thunder. This usually happens during thunderstorms, and sometimes during volcanic eruptions or dust storms.In the process of atmospheric electrical discharge, a bolt of lightning can travel at speeds of 60000 m/s and can reach temperatures approaching 30000 °C . There are approximately 16 million lightning storms in the world every year. Lightning can also occur within the ash clouds produced by volcanic eruptions or can be caused by severe forest fires that generate enough dust to create a static charge. Ice inside a cloud is known to be a key element in lightning development, and may possibly cause a forcible separation of the positive and negative charges within the cloud. This will then result in the formation of lightning. Lightning is an electrostatic discharge that occurs between the cloud and the ground, the cloud and other clouds or merely within a cloud.
a bolt of lightning is created when ...
opposite charges within the cloud attract one another. As the positive and negative areas grow more distinct within the cloud, an electric field is created between the oppositely-charged thunderstorm base and its top. The further apart these regions are, the stronger the electric field and and this will result in stonger attraction between the charges. However, the atmosphere is a good insulator of electicity. thus, a large amount of charge has to build up before the strength of the electrical field overpowers the atmosphere's insulating properties. A current of electricity forces a path through the air until it encounters something that makes a good connection. The current is discharged as a stroke of lightning.While all this is happening inside the storm, beneath the storm, positive charge begins to pool within the surface of the earth. This positive charge will shadow the storm wherever it goes, and is responsible for cloud-to-ground lightning. However, the electric field within the storm is much stronger than the one between the storm base and the earth 's surface, so about 75-80% of lightning occurs within the storm cloud.
this video shows a lightning stom that occured in HongKong , may 2003.
this video shows lightning striking Toronto CN tower.
Adrienna:D
___________________________________________________________________
Category:
0
comments
Light do travel in straight line. >>>>>
By: YuYing.
_______________________________________________________________
By: YuYing.
_______________________________________________________________
Category:
0
comments
Series and Parallel Circuits.
By, samantha.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Category:
0
comments
Tile: Biomass
Biomass is a renewable energy source because the energy it contains comes from the sun.
Types of biomass
Energy Crops, also called '' power crops'', could be grown on farms in potentially very large quantities, just like food crops. Trees and grasses,particularly those that are native to a region, are the best crops for energy, but other, less argriculturally sustainable crops such as corn tend to be used for energy purposes at present.
1)Trees
2)Grasses
3)Other crops
4)Oil plants
Biomass Residues
After plants have been used for other purposes, the leftover can be used for energy. The forestry, argricultural, and manufacturing industries generate plant and animal wastes in a large quantities.City wastes, in the form of garbage and sewage, is also a source for biomass energy.
The video below shows about 'energy from biomass'
This is another video shows that'' what is biomass''?
Biomass is a renewable energy source because the energy it contains comes from the sun.
Types of biomass
Energy Crops, also called '' power crops'', could be grown on farms in potentially very large quantities, just like food crops. Trees and grasses,particularly those that are native to a region, are the best crops for energy, but other, less argriculturally sustainable crops such as corn tend to be used for energy purposes at present.
1)Trees
2)Grasses
3)Other crops
4)Oil plants
Biomass Residues
After plants have been used for other purposes, the leftover can be used for energy. The forestry, argricultural, and manufacturing industries generate plant and animal wastes in a large quantities.City wastes, in the form of garbage and sewage, is also a source for biomass energy.
The video below shows about 'energy from biomass'
This is another video shows that'' what is biomass''?
Thank you!
Done By Xiaohong
Category:
0
comments
refraction is the change in direction of waves due to a change in its speed.this is most commonly observed when a wave passes from one medium to another at an angle.refraction is described as Snell's law which states that the angle of incidence is equal to the angle of refraction,it is also known as bending of light.
one of the effect of refraction is apparent deapth.we can conclude by doing an experiment by putting a coin into a basin and pour water into it. We would then see that the coin somehow floats.this happens when rays of lights from the hidden coin bend on reaching the water's surface and arrive at the eye,so that the coin could be seen.Refraction of light causes objects in water to appear shallower.so,this explains why the coin appears shallower then the actual height is.
Name:rachel
-------------------------------------------------------------------------------------------------
one of the effect of refraction is apparent deapth.we can conclude by doing an experiment by putting a coin into a basin and pour water into it. We would then see that the coin somehow floats.this happens when rays of lights from the hidden coin bend on reaching the water's surface and arrive at the eye,so that the coin could be seen.Refraction of light causes objects in water to appear shallower.so,this explains why the coin appears shallower then the actual height is.
Name:rachel
-------------------------------------------------------------------------------------------------
Category:
0
comments
Heyyyyyy (: Here's a short video on facts on electricity. It should cover some parts from the text book we use in school :
The video above show some safety measure in homes. Here are more safety measure in Singapore:
Do not join cut or frayed electrical cords together with insulation tape as this may peel off after a while and leave wires exposed. Get a licensed electrical worker to replace the cord with a new one instead.
Running wires around sharp edges can cut their insulation and expose live wires which are dangerous.
-/ Albert (:
________________________________________________________
The video above show some safety measure in homes. Here are more safety measure in Singapore:
Keep electricity and water apart!
Do not overload power points
Check the Earth wire
- Replace electrical cords with broken or frayed insulation
When water and electricity comes in contact, a spark could result. This spark may cause a fire in homes and cause damage to property.
Overloading power points is dangerous as it may lead to current leakage. So do not 'piggy back' multiple plugs into one socket by using double adaptors.
Don’t use cracked or broken power points/ extension socket outlets Replace cracked or broken power points/ sockets immediately with the help of a licensed electrical worker to prevent current leakage.
An unearthed plug can cause electric shock when there is a short circuit in an appliance.
Do not join cut or frayed electrical cords together with insulation tape as this may peel off after a while and leave wires exposed. Get a licensed electrical worker to replace the cord with a new one instead.
- Do not run wires around sharp edges
Running wires around sharp edges can cut their insulation and expose live wires which are dangerous.
-/ Albert (:
________________________________________________________
Category:
0
comments
Light.
There will be no refraction in the following conditions:
- Light travelling perpendicular to the boundary of the medium, even if they have different densities.
- Light passes through two mediums of the same densities.
Refractive Index
(http://www.datasync.com/~wizard/Lasers/Refraction348.jpg)
The speed of light is fastest in vacuum or air ( As compared to other mediums )
Alternatively , the refractive index ( n ) of a medium can also be defined as the ratio of speed of light in a vacuum to the speed of light in that medium.
Equation , n = Speed vacuum / Speed medium
Refractive index of a medium must be equal to or greater than ONE. The minimum value is ONE which is the refractive index of vacuum.
The greater the refractive index , the slower the speed of light in that medium.
Critical Angle
Critical angle refers to the angle of incidence in the optically denser medium which its angle of refraction in the less dense medium is 90°.
Since critical angle occurs when light passes through an optically denser medium to a less optically dense medium, to calculate the critical angle, we need to invert the constant [ n = ( sin i / sin r ) ] to [ n = ( sin r / sin i ) ] find the critical angle.
(http://nature.berkeley.edu/classes/eps2//wisc/jpeg/l5s2.jpeg)
Category:
0
comments
Teo Tong Kai
_____________________________________________________________________________________
Category:
0
comments
Title: Energy
Energy is:the ability to do work
in physics,energy is a scalar physical quantity that describes the amount of work that can be performed by a force,an atribute of objects and systems that is a subject to a conservation law.forms of energy include kinetic,potential,thermal,gravitational,sound,light and elastic.the forms of energy are often named after a related force.
http://www.youtube.com/watch?v=klFoqqgLHCA
by: Tan Yane,2E3
_________________________________________________________________
Energy is:the ability to do work
in physics,energy is a scalar physical quantity that describes the amount of work that can be performed by a force,an atribute of objects and systems that is a subject to a conservation law.forms of energy include kinetic,potential,thermal,gravitational,sound,light and elastic.the forms of energy are often named after a related force.
http://www.youtube.com/watch?v=klFoqqgLHCA
by: Tan Yane,2E3
_________________________________________________________________
Category:
0
comments
Hello, ok, I wanted to recap about energy, non-renewable. So, here's a video that shows you how non-renewable energy is being converted to electricity.
p.s// Let's save the Earth :D
- Afiqah. 2e3
p.s// Let's save the Earth :D
- Afiqah. 2e3
Category:
0
comments
hi this is my post,
Light travels both in straight lines and through reflection, which is a process in which light enters a prism and bends. Discover how light bends when going from one material to another with information from a science teacher in this video on physical science.
This is another video that shows about the refraction of light.
After viewing this 2 videos,let me explain again about light.Light,is an important source of energy,it enables us to see.Light also travels in straight lines because if it doesn't,what we see will not be accurate.A better example on whether light travels in straight lines are shown below.
as you can see,light travels through the holes in a straight horizontal position to the eye because it is traveling in straight lines.
Reflection,can occur when the light rays hit the surface of another medium.These mediums can be either mirrors,glasses or things that has a smooth surface.There also different types of mirrors,e.g:Plane Mirrors,Concave Mirrors and Convex Mirrors.
Images reflected in a plane mirrors has Characteristics.These characteristic are shown below.
Characteristics: -Distance of the image from the mirror is equal to the distance
of the object from the mirror.
-Same Size
-Upright
-Laterally Inverted
-Virtual
Refraction,occurs when light travels from one medium into another medium of different density(e.g AIR to WATER).The light changes its direction and bends when refracted.Light travels at different speeds for different materials.The speed of light depends on the optical density of the material.Light travels at slower speed in materials which has a higher optical density.TheBending of light is caused by changes in speed of light.
Done By R0n@Ll) Class:2e3 Index Number:34 :)
Light travels both in straight lines and through reflection, which is a process in which light enters a prism and bends. Discover how light bends when going from one material to another with information from a science teacher in this video on physical science.
This is another video that shows about the refraction of light.
After viewing this 2 videos,let me explain again about light.Light,is an important source of energy,it enables us to see.Light also travels in straight lines because if it doesn't,what we see will not be accurate.A better example on whether light travels in straight lines are shown below.
as you can see,light travels through the holes in a straight horizontal position to the eye because it is traveling in straight lines.
Reflection,can occur when the light rays hit the surface of another medium.These mediums can be either mirrors,glasses or things that has a smooth surface.There also different types of mirrors,e.g:Plane Mirrors,Concave Mirrors and Convex Mirrors.
Images reflected in a plane mirrors has Characteristics.These characteristic are shown below.
Characteristics: -Distance of the image from the mirror is equal to the distance
of the object from the mirror.
-Same Size
-Upright
-Laterally Inverted
-Virtual
Refraction,occurs when light travels from one medium into another medium of different density(e.g AIR to WATER).The light changes its direction and bends when refracted.Light travels at different speeds for different materials.The speed of light depends on the optical density of the material.Light travels at slower speed in materials which has a higher optical density.TheBending of light is caused by changes in speed of light.
Done By R0n@Ll) Class:2e3 Index Number:34 :)
Category:
0
comments
What Causes a spoon in a glass of water to appear distorted ???
When light ray travels from one medium(air) to another medium of different density(water/glass), the light ray changes its direction and bend. This bending of light is Refraction.
When white light passes through a prism,it will split into different colours.
Why??
Because different colours have different angles of refraction..
then a spectrum of colours is produced which is made up of 7 colours which makes up the rainbow.
Red,Orange,Yellow,Green,Blue,Indigo,Violet.
-Ilham
Azn4Lyfe
When light ray travels from one medium(air) to another medium of different density(water/glass), the light ray changes its direction and bend. This bending of light is Refraction.
When white light passes through a prism,it will split into different colours.
Why??
Because different colours have different angles of refraction..
then a spectrum of colours is produced which is made up of 7 colours which makes up the rainbow.
Red,Orange,Yellow,Green,Blue,Indigo,Violet.
-Ilham
Azn4Lyfe
Category:
0
comments
Light, how are rainbows formed.
Rainbow is arch formed by light refracted by drops of water diffused in the air.
You can see it when you have sun behind your back and you look at the rain.
In the brightest or primary bow, often the only one seen, the colors are arranged with the red outside. Above the perfect bow is a secondary bow, in which the colors are arranged in reverse order; this bow is dimmer, because of a double reflection within the drops.
When the sunlight enters a raindrop it is refracted, or bent, by and reflected from the drop in such a way that the light appears as a spectrum of colors. The colors can be seen, however, only when the angle of reflection between the sun, the drop of water, and the observer's line of vision.
You can test it out actually ;
Take flat container, pour some water in it and place a mirror in the water (mirror has to be partly in the water, partly out of the water).
You can see it when you have sun behind your back and you look at the rain.
In the brightest or primary bow, often the only one seen, the colors are arranged with the red outside. Above the perfect bow is a secondary bow, in which the colors are arranged in reverse order; this bow is dimmer, because of a double reflection within the drops.
When the sunlight enters a raindrop it is refracted, or bent, by and reflected from the drop in such a way that the light appears as a spectrum of colors. The colors can be seen, however, only when the angle of reflection between the sun, the drop of water, and the observer's line of vision.
You can test it out actually ;
Take flat container, pour some water in it and place a mirror in the water (mirror has to be partly in the water, partly out of the water).
Now place the container in front of the window that the part of mirror (one of of the water) reflects sunlight towards the wall.
You can see a small rainbow on the wall under the reflected white light.
(see the picture above. )
Thankyou.
Done by, Nadhirah 2E3 :D
___________________________________________________________________________________
Category:
0
comments
Reflection & Refraction of light
Reflection : The reflection of light is often discussed using phrases such as "a ray of light bounces off of a mirror." This is because when a light ray reflects at the surface of a mirror it follows a path similar in behavior to a pool ball bouncing off of a cushion on a pool table. However unusual it may sound at first, it is not really the best idea to describe the reflection of a light ray using words like bounce. It is better to describe light ray reflection as the turning back of the ray when it encounters the edge of a medium. Light rays, at least at first study, are best not quickly described in terms of particles, say, like pool balls.
Refraction : Refraction is the change in direction of a wave due to a change in its speed. This is most commonly observed when a wave passes from one medium to another at an angle. Refraction of light is the most commonly observed phenomenon, but any type of wave can refract when it interacts with a medium, for example when sound waves pass from one medium into another or when water waves move into water of a different depth. Refraction is described by Snell's law, which states that the angle of incidence θ1 is related to the angle of refraction θ2 by
where v1 and v2 are the wave velocities in the respective media, and n1 and n2 the refractive indices. In general, the incident wave is partially refracted and partially reflected; the details of this behavior are described by the Fresnel equations.
`Jolyn, [:
____________________________________________________________________
Reflection : The reflection of light is often discussed using phrases such as "a ray of light bounces off of a mirror." This is because when a light ray reflects at the surface of a mirror it follows a path similar in behavior to a pool ball bouncing off of a cushion on a pool table. However unusual it may sound at first, it is not really the best idea to describe the reflection of a light ray using words like bounce. It is better to describe light ray reflection as the turning back of the ray when it encounters the edge of a medium. Light rays, at least at first study, are best not quickly described in terms of particles, say, like pool balls.
Refraction : Refraction is the change in direction of a wave due to a change in its speed. This is most commonly observed when a wave passes from one medium to another at an angle. Refraction of light is the most commonly observed phenomenon, but any type of wave can refract when it interacts with a medium, for example when sound waves pass from one medium into another or when water waves move into water of a different depth. Refraction is described by Snell's law, which states that the angle of incidence θ1 is related to the angle of refraction θ2 by
where v1 and v2 are the wave velocities in the respective media, and n1 and n2 the refractive indices. In general, the incident wave is partially refracted and partially reflected; the details of this behavior are described by the Fresnel equations.
`Jolyn, [:
____________________________________________________________________
Category:
0
comments
ELECTRICITY(high voltage)
High voltage may lead to death when it is used wrongly.Do handle the electricity properly,it can also conduct electricity current when it come it contact with wood.Electric current flow from positive to negative is called conventional currentg flow.The current flow from negative to positive is called electron flow.The current is one amphere when a charge of one coulomb flow past every second.High electricity current may spoil a resistance and cause a short circuit.
jack 2e3
-jack
____________________________________________________________
High voltage may lead to death when it is used wrongly.Do handle the electricity properly,it can also conduct electricity current when it come it contact with wood.Electric current flow from positive to negative is called conventional currentg flow.The current flow from negative to positive is called electron flow.The current is one amphere when a charge of one coulomb flow past every second.High electricity current may spoil a resistance and cause a short circuit.
jack 2e3
-jack
____________________________________________________________
Category:
0
comments
Light
Light is a form of energy and can be transformed into other forms of energy. You would have observed the path of 'a beam of light' inside a room. This beam is nothing but the scattered light produced by the dust particles. Beam of light becomes invisible if the room is dust free. Thus light makes things visible.Light does not require a material medium for its propagation. In a given medium light travels with a very high but finite velocity.
Reflection Of Light
When a ray of light hits a surface, it bounces off or reflects and then reaches our eyes. This phenomenon by which a ray of light changes the direction of propagation when it strikes a boundary between different media through which it cannot pass is described as the reflection of light.Or in simpler words reflection is the bouncing of light from a smooth surface. (:
When a ray of light reach the boundary between two different substances, some light is reflected, and some light is refracted. The semi-cylindrical piece of glass has a higher index of refraction than air.
SAKINAHHHHHHHHHHHHHHHHHHHHHHHHHH izme. ;D
________________________________________________________________
Light is a form of energy and can be transformed into other forms of energy. You would have observed the path of 'a beam of light' inside a room. This beam is nothing but the scattered light produced by the dust particles. Beam of light becomes invisible if the room is dust free. Thus light makes things visible.Light does not require a material medium for its propagation. In a given medium light travels with a very high but finite velocity.
Reflection Of Light
When a ray of light hits a surface, it bounces off or reflects and then reaches our eyes. This phenomenon by which a ray of light changes the direction of propagation when it strikes a boundary between different media through which it cannot pass is described as the reflection of light.Or in simpler words reflection is the bouncing of light from a smooth surface. (:
When a ray of light reach the boundary between two different substances, some light is reflected, and some light is refracted. The semi-cylindrical piece of glass has a higher index of refraction than air.
SAKINAHHHHHHHHHHHHHHHHHHHHHHHHHH izme. ;D
________________________________________________________________
Category:
0
comments
Wednesday,Feb3/2010 @ 2.37PM
Potential Difference
The voltage between two (electron) positions "A" and "B", inside a solid electrical conductor (or inside two electrically-connected, solid electrical conductors), is denoted by (VA − VB). This voltage is the electrical driving force that drives a conventional electric current in the direction A to B. Voltage can be directly measured by a voltmeter. Well-constructed, correctly used, real voltmeters approximate very well to ideal voltmeters. An analogy involving the flow of water is sometimes helpful in understanding the concept of voltage (see below).
Precise modern and historic definitions of voltage exist, but (due to the development of the electron theory of metal conduction in the period 1897 to 1933, and to developments in theoretical surface science from about 1910 to about 1950, particularly the theory of local work function) some older definitions are no longer regarded as strictly correct. This is because they neglect the existence of "chemical" effects and surface effects. A particular lesson from surface science is that, to get consistency and universality, formal definitions must relate to positions or (better) electron states inside conductors.
In conduction processes occurring in metals and most other solids, electric currents consist almost exclusively of the flow of electrons in the direction B to A. This movement of electrons is controlled by differences in a so-called "total local thermodynamic potential" often denoted by the symbol µ ("mu"). This parameter is often called the "local Fermi level" or sometimes the "(local) electrochemical potential of an electron" or the "total (local) chemical potential of an electron". The modern electron-based definition of voltage (VA − VB) is in terms of differences in µ:
where e is the elementary positive charge. It is sometimes convenient to put µB=0 and VB=0, and choose position "B" so that it can be a convenient reference zero for V. It is common to choose position "B" to be inside a good electrical conductor solidly connected (by a very-low-electrical-resistance path) to the local "Earth" or "Ground". In the analysis of electrical circuit diagrams, it is common to show the point in the circuit that is being taken as the reference position B, by attaching a "Ground" ("Earth") symbol to this point.
A common misapprehension is to assume that difference in voltage is always equal to difference in electric potential (i.e. electrostatic potential). This is often untrue, because differences in "chemical effects" (e.g., as between conductors made from different materials) also contribute to differences in µ, and hence to differences in voltage. Some textbooks (especially old physics textbooks) give historic definitions of voltage that are not strictly equivalent to the modern definition. However, the difference in value between a "voltage difference" and the related "electric potential difference" is always small (at most a few volts, often less), and in many contexts it is commonplace (and acceptable) to disregard the distinction. Nonetheless, in some contexts, such as the theory of contact potential differences, the distinction is vital.
Done By, Lewis TAN 2E3
-----------------------------------------------------------------------------------------------------------------------------------------------------------
Post End
(Lewis Continued)
Potential Difference
The voltage between two (electron) positions "A" and "B", inside a solid electrical conductor (or inside two electrically-connected, solid electrical conductors), is denoted by (VA − VB). This voltage is the electrical driving force that drives a conventional electric current in the direction A to B. Voltage can be directly measured by a voltmeter. Well-constructed, correctly used, real voltmeters approximate very well to ideal voltmeters. An analogy involving the flow of water is sometimes helpful in understanding the concept of voltage (see below).
Precise modern and historic definitions of voltage exist, but (due to the development of the electron theory of metal conduction in the period 1897 to 1933, and to developments in theoretical surface science from about 1910 to about 1950, particularly the theory of local work function) some older definitions are no longer regarded as strictly correct. This is because they neglect the existence of "chemical" effects and surface effects. A particular lesson from surface science is that, to get consistency and universality, formal definitions must relate to positions or (better) electron states inside conductors.
In conduction processes occurring in metals and most other solids, electric currents consist almost exclusively of the flow of electrons in the direction B to A. This movement of electrons is controlled by differences in a so-called "total local thermodynamic potential" often denoted by the symbol µ ("mu"). This parameter is often called the "local Fermi level" or sometimes the "(local) electrochemical potential of an electron" or the "total (local) chemical potential of an electron". The modern electron-based definition of voltage (VA − VB) is in terms of differences in µ:
where e is the elementary positive charge. It is sometimes convenient to put µB=0 and VB=0, and choose position "B" so that it can be a convenient reference zero for V. It is common to choose position "B" to be inside a good electrical conductor solidly connected (by a very-low-electrical-resistance path) to the local "Earth" or "Ground". In the analysis of electrical circuit diagrams, it is common to show the point in the circuit that is being taken as the reference position B, by attaching a "Ground" ("Earth") symbol to this point.
A common misapprehension is to assume that difference in voltage is always equal to difference in electric potential (i.e. electrostatic potential). This is often untrue, because differences in "chemical effects" (e.g., as between conductors made from different materials) also contribute to differences in µ, and hence to differences in voltage. Some textbooks (especially old physics textbooks) give historic definitions of voltage that are not strictly equivalent to the modern definition. However, the difference in value between a "voltage difference" and the related "electric potential difference" is always small (at most a few volts, often less), and in many contexts it is commonplace (and acceptable) to disregard the distinction. Nonetheless, in some contexts, such as the theory of contact potential differences, the distinction is vital.
Done By, Lewis TAN 2E3
-----------------------------------------------------------------------------------------------------------------------------------------------------------
Post End
(Lewis Continued)
Category:
0
comments
What is electricity? This question is impossible to answer because the word "Electricity" has several contradictory meanings. These different meanings are incompatible, and the contradictions confuse everyone. If you don't understand electricity, you're not alone. Even teachers, engineers, and scientists have a hard time grasping the concept.
Obviously "electricity" cannot be several different things at the same time. Unfortunately we have defined the word Electricity in a crazy way. Because the word "electricity" lacks one distinct meaning, we can never pin down the nature of electricity. In the end we are forced to declare that there's no such stuff as "electricity" at all! Here's a quick example to illustrate the problem.
Do generators make electricity? To answer this question, consider the household light bulb. Inside a lamp cord the charges (the electrons) sit in one place and wiggle back and forth. That's AC or alternating current. At the same time, the waves of electromagnetic field move rapidly forward. This wave-energy does not wiggle, instead it races along the wires as it flows from the distant generators and into the light bulb. OK, now ask yourself this: when "electricity" is flowing, is it called an Electric Current? Yes? If so, then electricity is charge. And therefore we must say that the "electricity" sits inside the wires and vibrates back and forth. Generators do not create it, and it does not flow forward. Next, ask yourself if electricity is a form of energy. If it's energy, then electricity is made of electromagnetic fields, and it doesn't wiggle back and forth within the wires. Generators do create it, and it races along the wires at high speed. But electricity cannot do both! Which one is really "the electricity?" Is it the wiggling electrons, or is it the high-speed EM field energy? The experts cannot agree on a single definition. The reference books give conflicting answers, so there *is* no answer.
If someone asks whether generators make electricity, it exposes a great flaw in the way we talk about "electricity". If we can repair this flaw, perhaps our explanations will finally make sense. Below are the five most common meanings of the word Electricity. Which one do you think is right? Think about this carefully, because if one of these meanings is correct, all the others must be wrong! After all, no "science term" must ever possess several conflicting definitions. Unfortunately dictionaries and encyclopedias contain all of these contradictions. (Click the links to find out more about each one.)
1. The scientist's definition: "Electricity" means only one thing: it's the electrons and protons, the electric charge.
Examples: CURRENT OF ELECTRICITY. QUANTITY OF ELECTRICITY. COULOMBS OF ELECTRICITY.
2. The everyday definition: "Electricity" means only one thing: the electromagnetic field energy sent out by batteries and generators.
Examples: PRICE OF ELECTRICITY. KILOWATT-HOURS OF ELECTRICITY.
3. The grade-school definition: "Electricity" means only one thing: it refers to the flowing motion of electric charge.
Examples: "CURRENT" ELECTRICITY. AMPERES OF ELECTRICITY.
4. "Electricity" means only one thing: it refers to the amount of imbalance between quantities of electrons and protons.
Example: "STATIC" ELECTRICITY. DISCHARGE OF ELECTRICITY.
5. "Electricity" is nothing other than the classes of phenomena involving electric charges.
Examples: BIOELECTRICITY, PIEZOELECTRICITY, TRIBOELECTRICITY, THERMOELECTRICITY, ATMOSPHERIC ELECTRICITY ...ETC.
6. Other less common definitions:
"Electricity" refers to the flowing motion of electrical energy (electric power, Watts of electricity)
"Electricity" really means the electric potential or e-field (Volts of electricity)
"Electricity" only means the glowing nitrogen/oxygen plasma (sparks of electricity)
"Electricity" is nothing but a field of science (Basic Electricity, Advanced Electricity)
ELECTRICITY, n.The power that causes all natural phenomena not known to be caused by something else.(Ambrose Bierce, The Devil's Dictionary, 1911)
If we wish to agree on a single correct definition of "electricity," which definition should we choose? Well, maybe we don't need to choose just one. Suppose we ignore all these contradictions and instead pretend that ALL of the above definitions are true. Below is the "clear" and "simple" description of electricity that results:
Electricity is a mysterious incomprehensible entity which is invisible AND visible BOTH AT THE SAME TIME. Also, it's both matter and energy. It's a type of low-frequency radio wave which is made of protons. It is a mysterious force which looks like blue-white fire, and yet cannot be seen. It moves forward at the speed of light... yet it vibrates in the AC cord without flowing forwards at all. It's totally weightless, yet it has a small weight. When electricity flows through a light bulb's filament, it gets changed entirely into light. Yet no electricity is ever used up by the light bulb, and every bit of it flows out of the filament and back down the other wire. College textbooks are full of electricity, yet they have no electric charge! Electricity is a class of phenomena which can be stored in batteries! If you want to measure a quantity of electricity, what units should you use? Why Volts of electricity, of course. And also Coulombs of electricity, Amperes, Watts, and Joules, all at the same time. Yet "electricity" is a class of phenomena; it's a type of event. Since we can't have an AMOUNT of an event, we can't really measure the quantity of electricity at all... right?Heh heh. Does my description above sound stupid and impossible? You're right. It is. The word "electricity" has contradictory meanings, and I'm trying to show what happens when we accept more than one meaning. Electricity is not both slow and fast at the same time. It is not both visible and invisible.
Instead, approximately ten separate things have the name "electricity." There is no single stuff called "electricity." ELECTRICITY DOES NOT EXIST. Franklin, Edison, Thompson, and millions of science teachers should've had a long talk with Mrs. McCave before they decided to give a variety of independent science concepts just one single name.
Mrs. McCave was invented by Dr. Seuss. She had twenty three sons. She named them all "Dave."
Whenever we ask "WHAT IS ELECTRICITY," that's just like asking Mrs. McCave "WHO IS DAVE?" How can she describe her son? There can be no answer since the question itself is wrong. It's wrong to ask "who is Dave?" because we are assuming that there is only one Dave, when actually there are many different people. They all just happen to be named Dave. Who is Dave? Mrs. McCave cannot answer us until she first corrects our misunderstanding.
For the same reason, we will never find a simple answer to the question "what is electricity?" because the question itself is wrong. First we must realize that "electricity" does not exist. There is no single thing named "electricity." We must learn that, while several different things exist in wires, people wrongly call all of them by a single name.
So never ask "WHAT IS ELECTRICITY". Instead, discard the word "electricity" and begin using the correct names for all the separate phenomena. Here are a few of them:
What is electric charge?
What is electrical energy?
What are electrons?
What is electric current?
What is an imbalance of charge?
What is an electric field?
What is voltage?
What is electric power?
What is a spark?
What is electromagnetism?
What is electrical science?
What is electrodynamics?
What is electrostatics?
What are electrical phenomena?
The above questions all have sensible answers. But if you ask WHAT IS ELECTRICITY?, then all of the answers you'll find will just confuse you, and you'll never stop asking that question.
By Daniel
Obviously "electricity" cannot be several different things at the same time. Unfortunately we have defined the word Electricity in a crazy way. Because the word "electricity" lacks one distinct meaning, we can never pin down the nature of electricity. In the end we are forced to declare that there's no such stuff as "electricity" at all! Here's a quick example to illustrate the problem.
Do generators make electricity? To answer this question, consider the household light bulb. Inside a lamp cord the charges (the electrons) sit in one place and wiggle back and forth. That's AC or alternating current. At the same time, the waves of electromagnetic field move rapidly forward. This wave-energy does not wiggle, instead it races along the wires as it flows from the distant generators and into the light bulb. OK, now ask yourself this: when "electricity" is flowing, is it called an Electric Current? Yes? If so, then electricity is charge. And therefore we must say that the "electricity" sits inside the wires and vibrates back and forth. Generators do not create it, and it does not flow forward. Next, ask yourself if electricity is a form of energy. If it's energy, then electricity is made of electromagnetic fields, and it doesn't wiggle back and forth within the wires. Generators do create it, and it races along the wires at high speed. But electricity cannot do both! Which one is really "the electricity?" Is it the wiggling electrons, or is it the high-speed EM field energy? The experts cannot agree on a single definition. The reference books give conflicting answers, so there *is* no answer.
If someone asks whether generators make electricity, it exposes a great flaw in the way we talk about "electricity". If we can repair this flaw, perhaps our explanations will finally make sense. Below are the five most common meanings of the word Electricity. Which one do you think is right? Think about this carefully, because if one of these meanings is correct, all the others must be wrong! After all, no "science term" must ever possess several conflicting definitions. Unfortunately dictionaries and encyclopedias contain all of these contradictions. (Click the links to find out more about each one.)
1. The scientist's definition: "Electricity" means only one thing: it's the electrons and protons, the electric charge.
Examples: CURRENT OF ELECTRICITY. QUANTITY OF ELECTRICITY. COULOMBS OF ELECTRICITY.
2. The everyday definition: "Electricity" means only one thing: the electromagnetic field energy sent out by batteries and generators.
Examples: PRICE OF ELECTRICITY. KILOWATT-HOURS OF ELECTRICITY.
3. The grade-school definition: "Electricity" means only one thing: it refers to the flowing motion of electric charge.
Examples: "CURRENT" ELECTRICITY. AMPERES OF ELECTRICITY.
4. "Electricity" means only one thing: it refers to the amount of imbalance between quantities of electrons and protons.
Example: "STATIC" ELECTRICITY. DISCHARGE OF ELECTRICITY.
5. "Electricity" is nothing other than the classes of phenomena involving electric charges.
Examples: BIOELECTRICITY, PIEZOELECTRICITY, TRIBOELECTRICITY, THERMOELECTRICITY, ATMOSPHERIC ELECTRICITY ...ETC.
6. Other less common definitions:
"Electricity" refers to the flowing motion of electrical energy (electric power, Watts of electricity)
"Electricity" really means the electric potential or e-field (Volts of electricity)
"Electricity" only means the glowing nitrogen/oxygen plasma (sparks of electricity)
"Electricity" is nothing but a field of science (Basic Electricity, Advanced Electricity)
ELECTRICITY, n.The power that causes all natural phenomena not known to be caused by something else.(Ambrose Bierce, The Devil's Dictionary, 1911)
If we wish to agree on a single correct definition of "electricity," which definition should we choose? Well, maybe we don't need to choose just one. Suppose we ignore all these contradictions and instead pretend that ALL of the above definitions are true. Below is the "clear" and "simple" description of electricity that results:
Electricity is a mysterious incomprehensible entity which is invisible AND visible BOTH AT THE SAME TIME. Also, it's both matter and energy. It's a type of low-frequency radio wave which is made of protons. It is a mysterious force which looks like blue-white fire, and yet cannot be seen. It moves forward at the speed of light... yet it vibrates in the AC cord without flowing forwards at all. It's totally weightless, yet it has a small weight. When electricity flows through a light bulb's filament, it gets changed entirely into light. Yet no electricity is ever used up by the light bulb, and every bit of it flows out of the filament and back down the other wire. College textbooks are full of electricity, yet they have no electric charge! Electricity is a class of phenomena which can be stored in batteries! If you want to measure a quantity of electricity, what units should you use? Why Volts of electricity, of course. And also Coulombs of electricity, Amperes, Watts, and Joules, all at the same time. Yet "electricity" is a class of phenomena; it's a type of event. Since we can't have an AMOUNT of an event, we can't really measure the quantity of electricity at all... right?Heh heh. Does my description above sound stupid and impossible? You're right. It is. The word "electricity" has contradictory meanings, and I'm trying to show what happens when we accept more than one meaning. Electricity is not both slow and fast at the same time. It is not both visible and invisible.
Instead, approximately ten separate things have the name "electricity." There is no single stuff called "electricity." ELECTRICITY DOES NOT EXIST. Franklin, Edison, Thompson, and millions of science teachers should've had a long talk with Mrs. McCave before they decided to give a variety of independent science concepts just one single name.
Mrs. McCave was invented by Dr. Seuss. She had twenty three sons. She named them all "Dave."
Whenever we ask "WHAT IS ELECTRICITY," that's just like asking Mrs. McCave "WHO IS DAVE?" How can she describe her son? There can be no answer since the question itself is wrong. It's wrong to ask "who is Dave?" because we are assuming that there is only one Dave, when actually there are many different people. They all just happen to be named Dave. Who is Dave? Mrs. McCave cannot answer us until she first corrects our misunderstanding.
For the same reason, we will never find a simple answer to the question "what is electricity?" because the question itself is wrong. First we must realize that "electricity" does not exist. There is no single thing named "electricity." We must learn that, while several different things exist in wires, people wrongly call all of them by a single name.
So never ask "WHAT IS ELECTRICITY". Instead, discard the word "electricity" and begin using the correct names for all the separate phenomena. Here are a few of them:
What is electric charge?
What is electrical energy?
What are electrons?
What is electric current?
What is an imbalance of charge?
What is an electric field?
What is voltage?
What is electric power?
What is a spark?
What is electromagnetism?
What is electrical science?
What is electrodynamics?
What is electrostatics?
What are electrical phenomena?
The above questions all have sensible answers. But if you ask WHAT IS ELECTRICITY?, then all of the answers you'll find will just confuse you, and you'll never stop asking that question.
By Daniel
Category:
0
comments
The speed of light in a vacuum is presently defined to be exactly 299,792,458 m/s (approximately 186,282 miles per second). This definition of the speed of light means that the metre is now defined in terms of the speed of light. Light always travels at a constant speed, even between particles of a substance through which it is shining. Photons excite the adjoining particles that in turn transfer the energy to the neighbor. This may appear to slow the beam down through its trajectory in real time. The time lost between entry and exit accounts to the displacement of energy through the substance between each particle that is excited.
Another, more accurate, measurement of the speed of light was performed in
Electromagnetic spectrum
Generally, EM radiation (the designation 'radiation' excludes static electric and magnetic and near fields) is classified by wavelength into radio, microwave, infrared, the visible region we perceive as light, ultraviolet, X-rays and gamma rays.
The behavior of EM radiation depends on its wavelength. Higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths. When EM radiation interacts with single atoms and molecules, its behavior depends on the amount of energy per quantum it carries.
There are many sources of light. The most common light sources are thermal, sunlight, incandescent light bulbs and glowing solid particles in flames.
The peak of the blackbody spectrum is in the infrared for relatively cool objects like human beings. As the temperature increases, the peak shifts to shorter wavelengths, producing first a red glow, then a white one, and finally a blue color as the peak moves out of the visible part of the spectrum and into the ultraviolet. These colors can be seen when metal is heated to "red hot" or "white hot". Blue thermal emission is not often seen. The commonly seen blue colour in a gas flame or a welder's torch is in fact due to molecular emission, notably by CH radicals (emitting a wavelength band around 425 nm).
Category:
0
comments
Potential energy:
-Potential energy is exist whenever which has mass, has position within a force field. The potential energy of an object is given by a relation:
-Potential energy is exist whenever which has mass, has position within a force field. The potential energy of an object is given by a relation:
PE=mgh
where,
-PE=energy(in joules)
-m= mass(in kilograms)
-g=gravitational acceleration on the Earth(9.8m/s)
-h=height above earth's surface(in meters)
Kinetic Energy:
-Kinetic energy exist whenever an object in which has mass is in motion with some velocity. Kinetic energy of an object is given by a relation:
KE=1/2mv2
where,
-ke=energy(in joules)
-m=mass(in kilograms)
-v=velocity(in meters/s)
Conservation of energy:
-Energy can be change from one form to another, but cannot be created or destroyed.
-As the object falls and accelerates due to the earth's gravity, gravitational potential energy is converted to kinetic energy. When the object strikes the ground,all of the energy has to be in form of kinetic energy and the object is moving at its maximum velocity.
post end,
syazana(14)
____________________________________________________________________
Category:
0
comments
When the angle of incidence in water reaches a certain critical value, the refracted ray lies along the boundary, having an angle of refraction of 90-degrees. This angle of incidence is known as the critical angle; it is the largest angle of incidence for which refraction can still occur.
-Isy
Category:
isy yu=.=
0
comments
It shows that the direction of conventional current flows from a positive port to a negative port. However, after electrons were discovered, it became known that electron flows takes place from the negative terminal to the positive terminal. Still we use the conventional current flow to understand circuit. Voltage= Current Multiply resistance.
Category:
0
comments
Subscribe to:
Posts (Atom)