Date: Fri, 12 Sep 2003 14:27:28 -0500

Author: "Matt Lowry"

Subject: Re: Latent Heat

Post:

I do a great hands-on demo of this... I saw it a few years back in TPT.

Hand out marbles to your students - three each. Tell them that they
represent liquid water molecules, and their marbles represent bits of
kinetic energy. Have them get up and start interacting with one another
by walking around the room (since liquid molecules do slide past one
another) and playing "rock, paper, scissor" with another person.
Whoever wins the round gets an "energy bit" from the loser.
Continue...

... if a particular person (molecule) reaches six marbles (too much
kinetic energy), then they must zoom out of the liquid and become a gas
molecule. So then those students give me an "energy payment" (the
latent heat)of 2 marbles, and they then sit on the side away from the
liquid.

Continue this for a few minutes, and you can show a variety of thermal
phenomena:

1. distribution of molecular KE by inter-molecular collisions
2. phase changes
3. latent heat
4. evaporation as a cooling process; condensation as a warming
process

Not to mention, it's a fun activity that the students will enjoy in
addition to learning. Just try not to lose any of your marbles! :o)

Cheers,

Matt Lowry
Lake Forest HS
Lake Forest, IL


>>> Gerald_Zani@brown.edu 9/12/2003 1:51:09 PM >>>
Tappers,

How do people demonstrate latent heat?


Thanks,
Jerry
Gerald Zani e-mail: Gerald_Zani@brown.edu
Manager of Demonstrations phone: (401) 863-3964
Department of Physics FAX: (401) 863-2024
Brown University Providence, RI 02912-1843 USA

URL http://www.physics.brown.edu/users/staff/zani/index.html
URL http://www.physics.brown.edu/Studies/Demo/

Do a little more of that work which you have confessed to be good,
Which you feel that society and your most Just Judge rightly demand of
you.
Cultivate the tree which you have found to bear fruit in your soil.
If you have any experiments you would like to try, try them.
Now's your chance.
Henry David Thoreau, Journal entry, 1850.
From DWARN@boisestate.edu Fri Sep 12 13:11:08 2003

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