How can I keep my hot chocolate warmer for longer?

We thought of some materials that could be put around the cup to keep Guzzler's drink warm, these materials are called insulators. We decided to investigate two materials, tin foil and j-cloth and investigate which was the better insulator ie. kept Guzzler's drink warmer for longer.

First we had to collect the equipment that we would need to test materials in order to find out which was the best insulator.

3 paper cups

Thermometer

Warm water 

Tinfoil

J-cloth

We wrapped the tinfoil around one cup, the j-cloth around another, and left the third cup with nothing around it for the control (to compare).  

Once the cups were covered, we filled the three cups with equal amount of warm water, and ensured the starting temperature for each cup was equal. We checked the temperature of the three cups using a thermometer after 5,10 and 15 minutes to see which material had retained the most heat and was the best insulator.

I predicted the tinfoil will be the best insulator and retain the most heat, as the tinfoil would trap heat, whereas the j-cloth has holes which would allow heat the escape.

We predicted which we thought would be the better insulator.....

How did we make it a fair test?

Things we kept the same:

The type of cups- paper

The amount of water in each cup

The starting water temperature of each cup

The length of time we left them before checking the temperature.

In order for a test to be fair, all variables must stay the same, except one. Only one variable changes and that is the variable being tested.

Thing we changed:

The materials used to insulate the cups.