As you heat water to its boiling point, molecules are colliding with each other at high energy. Add your food to the pot, and watch the energy from the water heat up your food.
When you boil food in a pot of water on the stove, you cook it from the outside in. However, the boiling water is not always at a temperature of 212˚F. Higher air pressure or salt dissolved in the water can result in a higher boiling point.
You also use water to heat food in your microwave – but unlike the stovetop, it’s the water inside the food. The microwave radiation excites water molecules, causing them to hit other molecules and transfer heat to the food around them.
• Pot of water
• Ice cubes
With help from an adult, put the pot on the stove and heat until the water is boiling steadily.
While keeping the water boiling, place several ice cubes in the pot.
Observe what happens to the water.
When the ice cubes are added, the boiling should stop immediately as the heat flows to the coldest object in the pot. Similarly, when cooking, heat flows to the food in a pot of boiling water until it reaches the same temperature.