Keisha finds instructions for a demonstration on gas laws.

1. place a small marshmallow in a large plastic syringe.
2. cap the syringe tightly.
3. pull the plunger back to double the volume of gas in the syringe.

which best describes the purpose and outcome of the demonstration?

The purpose of this experiment is to demonstrate the relationship between pressure and volume. Pulling the plunger back increases the volume of the gas in the syringe thereby increasing the size of the marshmallow but pressure is reduced. The relationship to be demonstrated is that pressure and volume have an inverse relationship.