Phet Lab: Gas Properties and Particle Motion

1. Directions:
   Click Ideal on the screen. Then push and pull the PUMP handle up and down several times to add gas molecules into the box. Watch how the blue particles move.

3. Question:
   What does this show about air?

• Air is empty space with no matter.

• Air is made of solid chunks of oxygen.

• Air is made of tiny moving particles (molecules).

• Air doesn’t take up space.

Directions:

1. Stay on Ideal. Look at the pressure gauge as you pump more gas molecules into the box.

2. Observe what happens to the pressure.

4. Question:
   What happens when more air is pumped into the box?

• The pressure increases when more gas is added.

• The pressure decreases when more gas is added.

• The pressure stays the same.

• The temperature goes down.

Directions:

1. Stay on Ideal. Turn on the heat on the bucket to warm the gas molecules. Increase the Heat temperature.

2. Watch how gas particle speed changes.

4. Question:
   When temperature increases, what happens to gas particle motion?

• They move faster and hit the walls more often.

• They slow down and clump together.

• They stop moving.

• Temperature doesn’t affect movement.

Stay on Ideal. On the bucket, turn on Cool to lower the temperature.

1. Observe the gas particles.

3. Question:
   When temperature decreases, what happens to particle motion?

• They speed up and spread apart.

• They disappear.

• They slow down and move further apart

• They stay exactly the same.

Directions:

1. Stay on Ideal. Add only a few gas molecules (make sure box was empty beforehand). Note the pressure gauge reading.

2. Pump in more gas and compare the pressure.

4. Question:
   How does adding more gas molecules affect pressure?

• Pressure decreases when there are more particles.

• Pressure stays the same.

• Temperature controls pressure only.

• Pressure increases as more particles are added.

Directions:

1. Keep the same number of gas molecules.

2. Turn on the Heat on the bucket and watch the pressure gauge.

4. Question:
   What happens to pressure when the gas is heated?

• Pressure decreases as they move faster.

• Pressure increases because particles move faster and hit the walls harder.

• Pressure stays the same.

• • Heat makes molecules disappear.

Directions:

1. Stay on Ideal. Keep the same number of molecules. Turn on Cool to lower temperature.

4. Question:
   What happens to pressure when the gas cools?

• Pressure increases as molecules move slower.

• Pressure stays constant.

• It depends on the gas type.

• • Pressure decreases because particles slow down and hit the walls less.

Directions:

1. Stay on Ideal. Grab the handle on the box with the gas molecules and pull it to the right to compress the box to a smaller size.

2. Watch the pressure gauge.

4. Question:
   What happens when the gas is compressed?

• Pressure decreases because the box shrinks.

• Pressure increases because the same number of particles are in a smaller space.

• Temperature drops.

• Nothing changes.

Directions:

1. Stay on Ideal. Expand the box by pulling the same handle to the left.

2. Watch the particles and pressure gauge.

4. Question:
   What happens when the gas expands into a larger volume?

• Pressure increases because space is bigger.

• The number of particles increases.

• • Pressure decreases because particles have more space and fewer collisions.

• • It causes the gas to freeze instantly.

Directions:
Think about everything you observed in the simulation. When the gas was heated, the pressure went up. When it cooled, the pressure went down. The same idea helps explain why different weather systems form on Earth.

Question:
Which statement best explains how warm and cold air create different types of weather?

• Cold air presses harder, creating high pressure just like heated gas in the box.

• Warm air that rises makes low pressure, but sinking air warms up as it’s compressed — that’s what gives us warm, clear high-pressure days.

• Cold air always rises and lowers pressure bringing sunny days.

• Air pressure never changes with temperature.