Re: [Phys-l] heat/energy

["Souder Dwight" <souder.dwight@crestviewschools.net>]

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: phys-l-bounces@carnot.physics.buffalo.edu 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
--
Hugh Haskell
mailto:hugh@ieer.org
mailto:haskellh@verizon.net

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, Grist.org
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