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Re: [Phys-l] heat/energy

One year, I had the students try making fire by the friction of two peices of wood. I had a group of boys who did it the traditional way by using a wooden dowel and a loose bow to rotate the dowel at a fast rate. I also had a group of girls, who figured it out a faster way of doing it, by placing the dowel in the chuck of a drill. After a few minutes of pressing it hard into the bottom board, they quickly got smoke and fire.


From: on behalf of Hugh Haskell
Sent: Thu 1/28/2010 10:01 AM
To: Forum for Physics Educators
Subject: Re: [Phys-l] heat/energy

At 07:34 -0500 01/28/2010, Anthony Lapinski wrote:

I'm looking for some simple activities for a heat investigation/lab.
Specifically, when two objects collide, I want to show how kinetic energy
(loss) changes to work, sound, and heat. I thought about just hammering a
nail. They can clearly see the nail going into the wood and hear the
noise. I tried this (driving the nail about 1.5 cm), but could not really
sense a temperature change in the nail and hammer head. I then tried
pounding a lead brick with a sledgehammer, but both felt cool to the
touch. Maybe this has to be done for a longer time?

Try driving a screw into a piece of wood with an electric
drill--preferably a self-tapoping screw like a deck screw (they have
them at Home Depot)--and then back it out immediately. It will be too
hot to touch.

Hugh Haskell

So-called "global warming" is just a secret ploy by wacko
tree-huggers to make America energy independent, clean our air and
water, improve the fuel efficiency of our vehicles, kick-start
21st-century industries, and make our cities safer. Don't let them
get away with it!!

Chip Giller, Founder,
Forum for Physics Educators