| C1-3 | Ball and ring. |
| Purpose: | To demonstrate the thermal-expansion of metals. |
| Description: | A ball and ring are constructed so that at room temperature the ball will not pass through the ring. The ring is then heated, and the ball passes through very easily. |
| References: | Na-7 |
| Equipment: | Ball and ring, heat source such as gas, propane fuel or multi purpose lighter. |