When Things Go Bump

Invite your child to observe the three balls. Ask your child questions about what they notice. For example, "What size are they? How heavy are they?"

Practice rolling the two balls that are the same back and forth with your child. Give the ball a push, and watch it roll! Try rolling the balls fast. Try rolling the balls slowly. Don’t let the balls bump each other! What does your child notice? For example, what kind of push makes the ball go fast? What kind of push makes the ball go slowly?

What does your child think will happen if the balls bump into each other? Try it out! You and your child can try rolling the balls so they bump into each other. What does your child notice? Ask your child, "When the ball got bumped, what did it do? Which way did the ball move after it got bumped?" Point out to your child that a bump is a kind of push. When the balls bump, they push on each other.

Place one heavy ball and one light ball on the floor. Invite your child to observe each ball. Encourage your child can pick up each ball and see what they notice. How are the balls alike? How are they different?

What does your child think will happen when these balls bump? Encourage your child to roll the heavy ball to bump the light ball. Try this a few times. Then, have your child roll the light ball to bump the heavy ball. Try this a few times.

Encourage your child to share what they noticed. What happened when the balls bumped? Ask your child to describe the directions that the ball moved. Invite your child to think of other questions to investigate. For example, they might want to find out:

• What happens if two balls that are the same bump into each other going fast?
• What happens if a heavy ball and a light ball bump into each other going fast?
• What happens if one ball is still, and the same kind of ball bumps into it?

After your child has thought of a few questions, encourage your child to test out their ideas!