Which is the best heat holder?

Equipment:

• 4 cups of approximately same size and shape (one metal, one glass, one plastic, one paper)
• hot water
• icecream container
• measuring jug
• 4 thermometers

Method:

Place the 4 cups inside the icecream container to catch any spills.

Carefully pour an equal amount of hot water into each cup.

Use the thermometer to check that the water in each cup is at the same temeprature.

At 2 minute intervals, record the exact temperature of the water in each cup.

• Which cup keeps the water hot for longest? (In other words, which is the best insulator of heat?)
  
• Which cup would be the best for keeping a hot drink hot?
  
• Which cup would be the best for keeping a cold drink cold?
  
• Were your answers to the last two questions the same? If so, why?