Getting a Golf Ball Into A Baby Food Jar?

Key Concepts

• Thermal expansion and contraction: Materials change in size (expand or contract) with changes in temperature.
• Dry ice: Solid carbon dioxide, extremely cold (-110°F or -79°C), used to rapidly cool objects.
• Molecular movement: Molecules move faster and spread out at higher temperatures, and slow down and move closer together at lower temperatures.

The Golf Ball in a Jar Puzzle

The puzzle involves getting a standard golf ball into a baby food jar, where the golf ball's diameter is larger than the jar's opening. The presenter emphasizes that it seems impossible at first glance.

The Science Secret: Thermal Contraction

The solution lies in understanding thermal expansion and contraction. To get the golf ball into the jar, one must either increase the size of the jar's opening or decrease the size of the golf ball. Heating the jar is deemed impractical due to the risk of cracking.

The presenter proposes cooling the golf ball. When materials cool, their molecules move closer together, causing them to contract. The goal is to shrink the golf ball's diameter enough to fit through the jar's opening.

The Role of Dry Ice

Simply placing the golf ball in a standard freezer (around 0°F) won't suffice, as it won't get cold enough to significantly shrink the golf ball.

Dry ice (frozen carbon dioxide) is introduced as the key ingredient. Its extremely low temperature (-110°F) makes it ideal for rapidly cooling the golf ball. The presenter emphasizes the danger of handling dry ice with bare hands.

The Process: Step-by-Step

1. Place golf balls inside a container with dry ice.
2. Allow the golf balls to cool down significantly in the dry ice.
3. Carefully remove a golf ball from the dry ice.
4. Quickly attempt to insert the cooled golf ball into the baby food jar.
5. If successful, the golf ball will fit inside the jar.

The Result and the Time Constraint

The presenter successfully demonstrates the process, inserting a golf ball into the jar. He emphasizes that the effect is temporary. As the golf ball warms up, it will expand back to its original size. Eventually, it will become impossible to remove the golf ball from the jar.

The "Bet You Can't" Element

The puzzle is presented as a "bet you can't" challenge because it appears impossible without understanding the science behind thermal contraction. The presenter suggests giving the puzzle as a gift with a note, knowing that the recipient will be baffled until they learn the secret.

Conclusion

The golf ball in a jar puzzle is a demonstration of thermal contraction. By using dry ice to significantly cool a golf ball, its diameter can be temporarily reduced, allowing it to fit into a smaller opening. The puzzle highlights the practical application of scientific principles in everyday situations.