From: Raleigh McLemore (raleighmclemore@yahoo.com)
Date: Mon Dec 13 2004 - 16:50:30 PST
Message-ID: <20041214005030.7362.qmail@web54706.mail.yahoo.com> Date: Mon, 13 Dec 2004 16:50:30 -0800 (PST) From: Raleigh McLemore <raleighmclemore@yahoo.com> Subject: Re: pinhole Heat and Temp. lesson ideas??
There's a lot of stuff to do. My (younger) students have gotten a big kick out of the Sodium acetate packets they have at RAFT (one of Paul's inventions?). You snap a small metal disc inside of a clear sealed packet of Sodium acetate and the liquid not only changes to a crystal solid before your eyes, but creates quite a bit of heat. I got these packets, 20 in a set, for $1.00 per set. This is a lot of fun and introduces all produces all kind of interesting questions.
Another fun, but terribly messy, experiment is to do "blubber" as an insulator. You cover students gloved hands with Crisco and compare the "blubber insulation" hand with an uninsulated gloved hand in ice water.
Using hot and cold water you can also create thermal layers in small tanks, have them find the boundary, (give them thermometers, food coloring, ice and other stuff and let them report on their method.) Or you can just do the slow pour of icy, colored water water into slightly warm water and have the students sketch and report on what they are seeing and why they think the water behaves that way.
Filling a garbage bag with hot air and letting it drift over head is also interesting, and if you accidently set fire to the bag that is even more interesting. Imagine that, all the students writing furiously as the class erupts into flames and you saying..."Hurry with your observations, there isn't much class left!" Well, maybe it's best to be careful on this one, but seeing the garbage bag floating in the air is a great "heat/density" kind of thing.
Anothere good demonstration is to use the brass ring and ball (when cool the ball slips nicely through the ring), can't remember what you call them. The ring and ball are on separate metal rods. If you heat the ball it expands enough that it will no longer fit through the ring. If you heat the ring, the hot ball will drop right through. This, by the way is the principal of the 1600 cc Datsun engine ring gear. You had to heat the damn thing up till it practically glowed then start pounding it on the flywheel like a blacksmith. As it cooled it never, ever, moved again, held simply by the different size caused by heat.
Finally, if you have the time and inclination, you can invite your local firefighter to bring a hook an ladder truck to your school and have them talk about fire and heat. This, with the right firefighter, is really interesting, even the sleeping students begin to stir, or at least stop drooling softly on the desk.
With firm handshake,
Raleigh
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