Prototype #1

Prototype #2

Prototype #3

Prototype Procedures

Prototype Graphs

Final Thermos

In our final thermos, we used a styrofoam cup, a paper cup, 1 foam insulator, and 6″ by 3″ aluminum foil around cup and 3″ by 3″ for lid. The price was 3$ and the starting temperature was 80 degrees and lowered to 56 degrees which resulted in a 24 degrees difference.

We decided to use aluminum foil because it is a good insulator and reflects heat back to the source. The shiny side had to be facing the cup so the heat was reflected back. The aluminum foil was wrapped around the Styrofoam cup. The styrofoam cup is a good insulator because in it there are trapped gas bubbles. Gasses obstruct heat conduction because their molecules are far apart and make it difficult for other molecules to collide with them. We then put the styrofoam cup wrapped with foil and foam insulation in a paper cup. We choose the paper cup because it had a lower thermal conductiviy than a plastic cup. There are air pockets in-between the two layers of paper and plastic. Then The aluminum foil as a lid with the shiny side facing the water to reflect the heat back in. At first we didn’t thin aluminum foil was the best option because it absorbs heat but we researched more and found out its good to reflect heat back to the source. We tried using a plastic cup in prototype #2 because it was cheeper than a paper cup. After we realized paper would be a better investment because the plastic cup was moist after and didn’t do a good job of keeping the heat in. Another problem we realized after prototype #3 was where the lid was placed.  We had a Styrofoam cup inside a paper cup with foam insulation and cotton balls. We then placed the masking tape on top of the paper cup. The heat was escaping the styrofoam cup and effecting the cotton balls and foam insulation. For our final thermos we decided to put the lid around the Styrofoam cup only which made a big difference.