What is the fourth state of matter?
Why do puddles shrink in the sunshine?
How do greenhouse gases threaten life on Earth?
Matter is anything in the entire universe that takes up space and has mass. The amount of space an object occupies is the object's volume. For example, a golf ball and a ping-pong ball are about the same size. They take up about the same amount of space, so they have about the same volume. Mass is a measure of how much matter is in something. Even though the golf ball and the ping-pong ball have about the same volume, the golf ball is heavier. There is more matter in a golf ball. A golf ball's mass is greater than that of a ping-pong ball.
