My class is learning about the scientific method and about heat. So last week, we took time to answer the question:
Why do we heat up water before making tea?
We did this with the following experiment:
Control: 1 cup of water – 3 glasses; 1 tsp of loose leaf tea per glass
Variable: the temperature of the water
1.) Place one cup of water in the refrigerator for 10 minutes.
2.) Place the second cup of water in a pan and bring it to a boil.
3.) Leave the third cup of water to sit at room temperature.
4.) Add 1 teaspoon of loose leaf tea to each glass.
Students should observe that molecules are moving much faster in the hotter cup, a little bit in the room temperature cup and almost not at all in the cold cup. The tea leaves in the hot water move around the cup quickly and then settle on the bottom of the cup. The majority of the tea leaves in the cold water stay at the top of the cup. If you can, leave the cups to sit overnight and watch how much darker the hotter cup becomes.
What experiments do you use to teach heat?