WireJockey644 Posted March 4, 2015 Posted March 4, 2015 (edited) Me and a classmate have to make a thermos to hold boiling water for a certain amount of time and keep the temperature as close to the original as possible, but we need help coming up with materials. Edited March 4, 2015 by WireJockey644
Endy0816 Posted March 4, 2015 Posted March 4, 2015 Insulating foam could work. Not sure on exact ratings but most home improvement stores carry canned versions. If you have the resources to create and maintain a vacuum that would work even better. 1
StringJunky Posted March 5, 2015 Posted March 5, 2015 (edited) Wrap a lidded plastic beaker of boiling water in baking foil. Put some poly/foam beads in the bottom of a box and put your beaker in the middle. Fill the remainder of the box with the beads. A made-to-measure bit of thick corrugated cardboard on top would be good. Close the box lid. In this setup you have utilised insulation of radiation with the foil, and the beads insulate the conducted heat. If you want to manage convected heat you could do the whole assemby, minus the box, in a metal air-tight screw-topped container and make the container hot (60+ oC) before screwing down the lid. This will lower the internal pressure around the beaker when the air cools down around it and make a partial vacuum. You could sit the assembly in very hot water to warm up the container. Get some oven gloves or similar for this operation. Edited to add: If you do the latter setup, it will try and float on the water so you will have to press it down. This will cause the water to rise around the assembly. Make sure the contaner/bowl and amount of hot water you use to warm it up won't overspill into the experinent or on your work surface. Edited March 5, 2015 by StringJunky 1
michel123456 Posted March 6, 2015 Posted March 6, 2015 I have seen this before. Have to dig for old threads here. http://www.scienceforums.net/topic/65598-building-a-thermos-out-of-household-items/ http://www.scienceforums.net/topic/74193-i-need-insulators-for-a-thermos-that-is-able-to-keep-water-warmer-than-25-c/
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