In this movie, children will learn about heat. Before beginning the topic, discuss why heat is important and how living things rely on this type of energy to live. Explain to children that they can see and feel examples of heat all around them. They can observe heat’s effects when they go outside in the sunshine and feel the warmth on their skin. At night, outdoor temperatures drop because their part of the Earth is not facing the Sun. The Sun is a source of light and heat for Earth, and nearly all living things rely on the Sun in order to survive. Cold-blooded animals, such as snakes, lizards, frogs, salamanders, and insects, cannot produce their own heat and rely on the Sun to warm their bodies.
We get heat from different sources. A fuel is something that can be burned for heat and energy. Wood, coal, charcoal, oil, gasoline, and natural gas are all examples of fuels. Children may be familiar with the term fossil fuel, which is oil, coal, or natural gas created from the geological remains of decomposing plants and animals.
Friction is the force that slows down moving objects. When two things rub together, they create friction. On a bike, there are two pieces of hard rubber that push against the tire when the brakes are engaged. The pieces of rubber rub against the tire, slowing it down to a halt. Explain that friction creates heat. Have children rub their hands together vigorously and feel the warmth between their palms. The friction caused by the rubbing creates heat. Encourage children to think of other examples of friction.
Heat can change matter in different ways. For example, by adding heat to an ice cube causes it to change from a solid to a liquid, or from a liquid to a gas. When water freezes, it loses heat and changes from a liquid to solid. You may want to watch the Changing States of Matter movie for further exploration of this topic. Heat can cause chemical changes, which is a change in the chemical composition of a substance to produce a new material with different properties. When we turn batter into a pancake, we are using heat to cook and chemically change the raw ingredients into something different.
Ask children to think about how we need and use heat. Children should be aware that heating our homes and fueling our cars take up a lot of natural resources, and the product of burning some fuels is air pollution. Less heat is necessary when homes are properly insulated or sealed with storm windows. Help children understand the concept of insulation by explaining that they insulate themselves from the cold by wearing sweaters, coats, or hats. Encourage them to think of ways to conserve heat and protect our resources.
After exploring this topic, you may want to share the Light movie to extend the unit.