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)?
man-made lightning storm:
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!
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
poles on a magnet
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 .
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.
that we added a 1 mega
ohm resistor going from the antenna to the FET. The antenna
be cut to a length that suits the sensitivity desired.
simple walking generates
an electric field that can be detected with this circuit.