We rigged up a loud beeper inside the vacuum chamber, as well as a baloon partially inflated, and a graduated cylinder of water. If I put warmed water in there, the cylinder boils rapidly after about a minute under vacuum. Room temperature water takes about ten minutes to start boiling, making for a boring demonstration. The baloon blows up to a great size, then flies all over the inside of the bell jar when I let the air bback in for a dramatic effect. When the water boils, it cools, so I put a thermocouple in there. When the water has cooled to say 85 F, I shut off the vacuum, lift off the bell jar and drink the water that was just boiling. Maybe I will try a marshmallow, too! We also found a high voltage supply, and are rigging up a little sparky stuff. --Lawrence ----- Original Message ----- From: "Alex Holden" To: Sent: Tuesday, May 21, 2002 5:25 PM Subject: Re: [OT]: Demos for Kids (Was NCSU Physics demo room) > Lawrence Lile wrote: > > Tomorrow I have to put on a show for some first grade 7 year olds in my lab. > > In the past, I trotted out this old vacuum chamber that we never use for > > anything else. I usually boil some room temperature water in it, then take > > it out and drink it down, put a small ballooon in it and watch it get big > > under vaccuum, and the like. This time I'm thinking about putting a candle > > flame inside and watching it go out. > > You could put a ringing electric bell or siren in it to demonstrate that > sound doesn't travel through a vacuum. > > -- > ------------ Alex Holden - http://www.linuxhacker.org ------------ > If it doesn't work, you're not hitting it with a big enough hammer > > -- > http://www.piclist.com hint: To leave the PICList > mailto:piclist-unsubscribe-request@mitvma.mit.edu > > -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads