For our thermos project we had to create a thermos within the range of $3.00 that wouldn’t decrease in temperature more than 20 degrees celsius from boiling point.

Our first prototype consisted of two styrofoam cups, aluminum foil, and sand.  We choose these materials because we know the Styrofoam cups trap in heat due to their small air pockets which blocks the energy flow.  In other words, it is useful to convecting heat.  We choose foil to radiate the heat back.  Finally we used sand to insulate the foil which radiated the heat back. In the end, we lost 18 degrees celsius in 10 minutes. At a cost of $2.70.

Our second prototype consisted of aluminum foil, a plastic cup and lid, a styrofoam cup, and sand.  We inserted the styrofoam cup into the plastic cup to change the insulator to see if it affected our temperature in any way.  We used the plastic lid to keep the heat inside the cup allowing the steam to not escape keeping hot.  In the end, we lost more heat than prototype one; 21 degrees celsius in 10 minutes.  At a cost of $2.25.

Our third prototype consisted of aluminum foil, tape, floor underlay, a lid, and a styrofoam cup.  We eliminated the extra cup and sand to make the thermos more compact allowing the heat to stay tighter creating greater thermal energy.  We added tape to help.  Finally, we added more aluminum foil and floor underlay under the lid to trap in more heat.  In the end, we lost 16 degrees celsius in 10 minutes.

Our final product consisted of a plastic lid, foam underlay, aluminum foil, tape, and two styrofoam cups.  We kept our materials the same to create convection and insulation while the foil conducted the heat, although we also added an extra styrofoam cup to put the other cup that is wrapped in foil to help the insulation for when the heat exits the first cup to the foil and radiates back, the second cup preventing heat loss as much as possible.  In the end, we lost 10 degrees celsius in 10 minutes.  At a cost of $3.50.