Make a thermal carafe out of leftover parts and trash!
The familiar Thermos Bottle is extremely useful as well as being a groovy science demonstration, but they can be a little expensive if you need a lot of them or plan to be careless with them.
A little research into how a thermos works can point the way to building an inexpensive substitute. Using a couple of plastic bottles, some insulating material, and simple tools, we can make a slapdash thermal carafe.
The slapdash thermal carafe build log shows the steps for building a homemade thermos.
Predicatably enough, a thermal carafe made from junk doesn't retain heat as well as the professionaly-manufactured one, but it does OK. I tested the performance of the slapdash thermal carafe against a real Thermos brand thermos. The test results show how it did.
Slapdash Thermal Carafe Summary Page
Thermos Bottle (at Thermos.com)
How a thermos works (at HowStuffWorks.com)
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