Children's Museum of Houston

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What you need

• Pom-poms, various sizes
• Yarn to make circles
• Paper and pencil

What to do

1. Cut a piece of yarn 9 feet long. Tie the ends together and place the yarn circle on the floor.
2. Lay a 1 foot long strip of yarn about 3 feet from the edge of the circle.
3. Choose 10 pom-poms.
4. Predict how many of the pom-poms you think will land inside the circle.
5. Toss all ten of the pom poms at the same time.
6. In order to be counted inside the circle, they must be inside the circle after they finish moving.
7. Gather the pom-poms and predict again.
8. Toss them again.
9. Cut a piece of yarn 6 feet long and make a new circle.
10. Predict how many will fall in the circle before each toss.

What to ask

• How many are inside?
• How many are outside?
• How close were you to your prediction?
• What are the most pom-poms that can fall inside the circle? The least?
• Do you predict more or less for the smaller circle than the bigger circle?
• How is the number of pom poms that fall inside the circle related to the size of the circle?
• How did you decide what to do when the pom pom was partly inside and outside the circle?
• What would happen to your prediction if you increased the number of pompoms to 20?

What’s next?

• Create your own size circle. Is it bigger or smaller than the ones you were using? How do you adjust your prediction for it?
• Place the smaller circle inside the larger one. How does this change your predictions for how many will fall into each circle?
• Throw the pom poms one at a time. Does this change your prediction?
• Change how far away you stand before throwing the pom-poms. How do you change your prediction when you are further away? When you are closer?