Setup Instructions

Question

Make sure the foam cup is filled with hot water. It should be one-quarter full.
Take the plastic cup and turn it upside down. Place it on top of the foam cup.
Observe any phase changes that occur, using the provided magnifying glasses as needed.
Answer the questions below.
What did you observe happening in the cups?

Did a phase change or phase changes occur? If so, which one or ones?

Answer 1

Observation in the Cups:

When the foam cup filled with hot water is covered with the upside-down plastic cup, you may observe condensation forming inside the plastic cup. Initially, the hot water heats the air between the foam cup and the plastic cup. This warm air can hold more moisture than cooler air. As the heat from the hot water warms the air, some of the water evaporates into vapor. When this vapor touches the cooler surface of the plastic cup, it cools down and condenses back into liquid water droplets.

Phase Changes Occurred:

1. Evaporation: The water in the foam cup heats up and some of it transitions from liquid to gas (water vapor) due to the heat.
2. Condensation: The water vapor that rises to the top of the plastic cup cools upon contact with its cooler surface, transitioning from gas back to liquid forming droplets.

In summary, both evaporation and condensation are the phase changes observed during this experiment.