Re: Cool Demo for Newton's First Law?

[Ludwik Kowalski <kowalskil@MAIL.MONTCLAIR.EDU>]

Push a cart and show that its speed (on a smooth horizontal table top)
"tends to remain" constant. Then repeat the demo with a tin soldier (or
another object) in the cart.  Make sure the soldier is standing in the
middle after your hand (pushing the cart and the soldier) is released.
Show what happens when the cart with the soldier is stopped suddenly by
hitting a barrier. The soldier "tends to remain" in motion. Tell the
person who interviews you that you would ask students TO EXPLAIN such
observations.

In my opinion the explanation does not exist but attempts to explain
are worth making. Newton's first law is a generalization of numerous
observations; it is "an instrument" for explaining other things. The
second Newton law, on the other hand, does bring the "cause and effect"
idea into mechanics. It explains observations in terms of forces.
Ludwik Kowalski

On Wednesday, Jun 23, 2004, at 19:23 America/New_York, Dan Folmar wrote:

> Hello,
>
> I'm a new (prospective) teacher, and I have my second interview with a
> local high school tomorrow.  I need to deliver a 15 minute lesson on
> Newton's 1st law.  I'm looking for some good ideas for a "wow" demo
> that will deliver the message effectively and be easy to pull off.
> Right now, I'm thinking about wearing roller blades and ask one of the
> students to push me -- and then go into a discussion about constant
> velocity.
>
> Any other ideas will be appreciated!
>
> Thanks,
> Dan
>
>
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