Expansion of metal due to heat

Proposition:  To test if metal expands when heated.

Equipment: A small brass ball on a chain attached to a wooden handle, and a  little metal brass hoop also attached to a wooden handle. A portable gas stove. A bowel of cold water.

Experiment: First we tested that the ball would fit through the hoop. And it did. Next we turned on the gas stove and started heating up the hoop and ball. The scary bit was when the ball came off the chain and dropped into the fire. The ball fell off the chain because the heat was so intense that it melted the ring holding it on to the chain.

It had already expanded enough that it would not drop through the hoop onto the gas element, and would stay in the middle of the hoop.

The ball got stuck in the hoop because it had expanded so much that it couldn’t get out of the hoop.

While the ball and hoop were stuck together we put them in the bowel of water and it splattered and spat and sizzled lots. Then we took the hoop out but the ball stayed in the bowl because it had shrunk back to its normal size and could fit through the hoop again. 

Conclusion: We met our proposition by completing our experiment and doing it right. The ball and hoop did expand just like we planned!