Flicking on the Switch
In 1786 Luigi Galvani hung the legs of a dead frog on a railing in a thunderstorm to see if lightning would make them twitch….

Flicking on the Switch
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No he didn’t use Kermit

He believed he had created
“ Animal Electricity ” – and many people began to believe that this was the secret of life itself. By creating a static charge he and other scientists could get the dead frog’s legs to twitch…

However one day he made the legs twitch without any charge. It was
Alessandro Volta who realized why: the brass hooks on which the legs hung were reacting chemically with an iron stand to create an electric current .

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 Many believed that such electrical currents would bring the dead back to life. This is why
Mary Shellye’s famous story of Frankenstein, is brought to life by a massive electric shock from a bolt of lightening…

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But people can’t be brought back to life this way so lets continue about why the frog’s legs twitched without a charge
 Alessandro Volta discovered that the electricity came from the chemical reaction between the metal and the metal hook on which the legs hung. Knowing this, Volta made the first battery in 1800…

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 Batteries create a current chemically
 What is a current ?
 Imagine a row of marbles and you flick one hard, and the marble at the far end of the table shoots off. In any material that conducts electricity well, the marbles, properly called, electrons , move and hit the next one in line passing the electric current through the circuit creating electricity .

Flicking on the Switch
 Batteries create a current chemically
 To make an electric current flow, two things are needed:
 An unbroken path or circuit
 A driving force to push the electrons that carry the charge around the circuit – usually from a battery

Flicking on the Switch
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So from frog legs to batteries…
We have found a way to create electricity by creating a complete circuit - when you switch on anything electrical, you are simply making the final connection in the electrical circuit.

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 Circuits can be dangerous as they can carry thousands of volts of electricity
 Circuits need 3 main elements:
 A conductor through with the current flows – usually are copper wire and other metals
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A load , which is the equipment being powered
An energy source , such as the battery

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 Circuits can be controlled by the flick of a switch. Much like when you turn on and off your bedroom light.
 Switches interrupt the electron flow without you physically touching the wire…..

Flicking on the Switch
 There are many different types of switches: toggle, rotary, pushbutton, "rocker",
"pull-chain", slide, magnetic, all which assist you in stopping the electron flow temporarily.

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 Lets Review
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Alessandro Volta realized that the brass hooks on the which the frog legs hung were reacting chemically with an iron stand to create an electric current.
Volta made the first battery in 1800
Electrons , like marbles, move and hit the next one in line passing the electric current through the circuit creating electricity .
Two things are required to make a electric current flow:
Do you remember what they are?

Flicking on the Switch
 An unbroken path or circuit
 A driving force to push the electrons that carry the charge around the circuit – usually from a battery

Flicking on the Switch
 Circuits need 3 main elements:
 A conductor through with the current flows – usually are copper wire and other metals


A load , which is the equipment being powered
An energy source , such as the battery
 Circuits can be controlled by the flick of a switch.
Much like when you turn on and off your bedroom light

Flicking on the Switch
 Circuits can be controlled by the flick of a switch. Much like when you turn on and off your bedroom light.
 Switches interrupt the electron flow without you physically touching the wire…. because if you did the results could be deadly.

At this time producers, of “Flicking on the Switch” would like to state that at no time were any Muppets hurt during the making of this presentation.
Credits to:
How Science Works - Readers Digest - Hann, Judith. 1991
Google Images www.google.ca
http://www.energyquest.ca.gov/story/chapter04.html
http://www.1728.com/project2.htm