What You Need:
- Steel wool
- Put the thermometer in the jar and close the lid.
- Wait about 5 minutes and write down the temperature.
- Remove the thermometer from the jar.
- Soak a piece of steel wool in vinegar for 1 minute.
- Squeeze the vinegar out of the steel wool. Wrap the steel wool around the bulb of the thermometer.
- Place the thermometer and steel wool back into the jar and close the lid.
- Wait for five minutes.
- Write down the temperature. (Did you notice a change in temperature?)
The vinegar removes any protective coating from the steel wool, allowing the iron in the steel to rust. Rusting is a slow combination of iron with oxygen. When this happens, heat energy is released. The heat released by the rusting of the iron causes the mercury in the thermometer to expand and rise.