This electric force can be felt as "static
electricity" that can make your hairs stand
on end! Ever felt this from a TV or from a woollen
jersey (jumper)?
A man-made lightning storm:
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A special lightning machine
called a Van de Graaf generator uses friction
(rubbing) to generate lots of static electricity.
Here the electrons can be seen leaping back
to where they came from as a huge spark...a
lightning bolt!
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The static electricity
from this machine is safe to touch...Mikaela
is quite happy! Her whole body and the hairs
on her head have the same electric charge
so push away from each other...a bit like
two North
poles on a magnet push away...
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What creates thunder and lightning?
We said that two objects rubbing together create
static electricity. Think about the clothes coming
out of a tumble dryer...sometimes a sock is "stuck"
to a jersey...as you pull the sock off you can
here the crackle of electricity as tiny bolts
of lightning return electrons to where they belong.
What about at night when your remove a woollen
jersey? The same sort of rubbing on your body
creates the same sort of tiny lightning bolts.
Lets think BIG! Imagine the whole sky;
the air (as wind) rubbing against trees, houses,
people, the oceans, creating static electricity...LOTS
of it! This electricity finally is able released
as a giant electric spark...lightning. Unlike
our Van de Graaf machine, lightning electricity
can kill!
Here is a neat little circuit that can show how
far the invisible lines of electric force can
reach due to static electricity .
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A field effect transistor
(FET) is connected to a Light Emmitting
Diode (LED). One leg of the FET acts
as an antenna, able to switch the
LED on (or off!) depending on the
type of electric field nearby.
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Not the ideal base
to build a prototype circuit on but
it demonstrates one possible setup.
An alligator clip connected the the
antenna leg can make this electric
field detector more sensitive.
Even simple walking
generates an electric field that can
be detected with this circuit.
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