Heating and Cooling

Before Video

• Heat causes chocolate to melt. When something melts it changes from a solid to a liquid.

• Ice, ice cream, popsicles, chocolate and crayons all melt when heated up. Even metal can melt when heated, but it has to get extremely hot.

• It freezes into ice. Freezing is when something cools down and changes from a liquid to a solid.

• A reversible change is a change that can be undone or changed back. Melting and freezing chocolate is an example of a reversible change.

• Observable means we can see it with our eyes. Scientists use their senses to make observations and understand the world around us.

After Video

• Heating up marshmallows in a fire and heating up clothes with an iron are both examples of heating.

• Cooling down a drink with ice and cooling your breath due to the cold air outside are both common examples.

• Butter changes from a solid to a liquid when it is heated.

• A reversible change means the change can be undone. If the object that changed can go back to its original form, then it is reversible.

• Melting butter then cooling it and melting an ice cube then re-freezing it in the freezer are both common examples.

• Popcorn popping, cooking eggs, making cupcakes, and lighting something on fire are all common examples. You know it’s non-reversible because it cannot change back to the original form.