MadSci Network: Physics Query:

### Re: can friction produce electricity?

Date: Fri Jan 17 01:32:38 2003
Posted By: Nauzad Tantra, Undergraduate, Production/ Industrial engg., D J Sanghvi college of engg.
Area of science: Physics
ID: 1042411007.Ph
Message:
```
Hi,
Can friction generate electricity? Thats a good question. The answer to
your question is yes and no. Here's why:

Why Yes? : If you rub a piece of plastic on your hair or on wool you would
generate what is known as static electricity. What you do while rubbing the
plastic is generate a charge on its surface. This charge can then flow into
an object that has the opposite charge. So by rubbing (friction) you can
create charges which are responsible for generating electricity. If you can
rub a very large number of particles, you may even be able to see a small
spark. Thats what creates lightning. The small particles in clouds rub
against each other at very high speeds. This creates a lot of charge, which
then flows down to the nearest object (another cloud or earth).
Some materials when struck against each other also produce a spark. Thats
how fire was made in the olden times. You struck two stones, or a stone
with a metal to create a spark, from which you started a fire.
So you can create electricity by friction.

Why No? : Friction usually produces a lot of heat. So if you tried to
produce a lot of electricity in this way, you would produce a lot more heat
than electricity. And that would be a terrible waste!! Secondly, it is not
yet been able to use the static electricity produced by friction. If it
were, than our lights and televisions would be running just on lightning!!
The electricity produced by static charges is usually very minute (small)
and not practical to use as a source of power.
Also the power produced does not last very long. Lightning for example, may
be able to power a 100W electric bulb for about a month. However, it takes
only a fraction of a second for lightning to strike. And we have no
batteries that can be charged that fast. So till now it has not been
possible to use friction to produce electricity.

I hope that helps.

```

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