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Science
Fire
It cooks our food and makes it taste better. It warms our homes and makes our cars go. Yet it can be hard to control. It can destroy a house or an entire forest. It is fire. Fire is both very useful and very dangerous.
HOW DO FIRES GET STARTED?
Three things are needed to get a fire going. The first is oxygen, a gas that makes up part of air. The second is fuel to burn. Fuel can be anything that will burn. In a campfire, for instance, the fuel is wood. In most car engines, the fuel is gasoline.
Force and Motion
You make forces all the time. Forces press on you, and you use them to press on objects. Pushing your foot against your bicycle pedal makes a force. The force sets the bike in motion. Every time something starts moving or stops moving, a force is responsible.
You use force to throw a ball in the air. The force of Earth’s gravity pulls the ball back down. Every step you take creates a force on your foot and on the ground. Forces and motion are part of everyday life.
EVERYTHING IS LAZY
Why do you have to push a shopping cart to get it started? Objects that are sitting still stay that way until something makes them move.
Light
When you get up in the morning, sunlight makes your room bright. When the Sun sets, your room gets so dark you might trip over the furniture. Without light, you cannot see. So you flick a switch on the wall and electric light makes your room bright again.
You know that you cannot see without light. But did you know that life on Earth would not be possible without light? Light from the Sun makes Earth warm enough for life. Light from the Sun makes green plants grow. Plants are food for animals.
Heat
Here’s a riddle: How is heat like a river? Answer: They both flow “downhill.” You will never see a river flow up a mountain. A river only goes one way, down. Heat also goes one way. Heat only flows from something that is hotter to something that is colder.
You might think that putting an ice cube in your lemonade makes the lemonade cooler. What really happens is that the lemonade makes the ice cube warmer. Heat goes out of the warmer lemonade into the colder ice cube. Heat only flows one way.
Matter
You cannot drink a steak or nail chunks of air together. You cannot chew milk or breathe wood.
Steaks, air, milk, and wood seem very different from one another. Yet all these things have one thing in common. They are types of matter. Matter is anything that takes up space. Look around. Every object you see is made of matter.
Matter comes in different forms. Matter can be solid like steaks and wood. It can be a gas like air. It can be a liquid like milk. Scientists call solids, liquids, and gases the ordinary “states of matter.”