Compressing Gases Gases hold huge amounts of energy, and their molecules are spread out as much as possible. With very little pressure, when compared to.

Compressing Gases• Gases hold huge amounts of energy, and their molecules are

spread out as much as possible. With very little pressure, when compared to liquids and solids, those molecules can be compressed. It happens all of the time. Combinations of pressure and decreasing temperature force gases into tubes that we use every day. You might see compressed air in a spray bottle or feel the carbon dioxide rush out of a can of soda. Those are both examples of gas forced into a smaller space than it would want, and the gas escapes the first chance it gets. The gas molecules move from an area of high pressure to one of low pressure.

Lesson Frame

• I can analyze how trapped gas reacts when temperature, volume or pressure are changed.

• I will observe several different situations and determine which variables are changing and how they are changing.

• I will have mastered this when I can identify gas laws based on how the variables are changing.

Gas Laws

At each lab station that you work at today, a gas (air) will be trapped in various types of containers. It will be your job to analyze how the trapped gas reacts when pressure, volume, and temperature are changed.

Demonstration:  Nice shot Spud!

• Observe the demonstration.– Determine whether or not the pressure, volume, and

temperature is increasing, decreasing or staying the same and record the data in your journal.

– Write a paragraph to describe your observations.

Pressure Volume Temper-ature

Increase, decrease, same

Gas Law

Station 1    Life in a Vacuum!

• Instructions:– Place a mini marshmallow into the “vacuum chamber" and push the plunger down so

that it stops just above the marshmallow. Wrap the plastic wrap around the open end. Place your finger over the open end and slowly pull the plunger out while observing the marshmallow.

– Determine whether or not the pressure, volume, and temperature is increasing, decreasing or staying the same and record the data in your journal.

– Write a paragraph to describe your observations.

Pressure Volume Temper-ature

Increase, decrease, same

Gas Law

Station 2     The Cartesian Diver• Instructions:

– The "diver" is the dropper which is inside the large plastic bottle. Note the position of the diver inside the bottle as the bottle sits on the table. Squeeze and release the bottle.

– Determine whether or not the pressure, volume, and temperature is increasing, decreasing or staying the same and record the data in your journal.

– Write a paragraph to describe your observations.

Pressure Volume Temper-ature

Increase, decrease, same

Gas Law

Station 3    Ivory Soap Flower• Instructions:

– Place a chunk of Ivory soap on a paper plate and place in the microwave. Turn on the microwave for 1-2 minutes.

– Determine whether or not the pressure, volume, and temperature is increasing, decreasing or staying the same and record the data in your journal.

– Write a paragraph to describe your observations.

Pressure Volume Temper-ature

Increase, decrease, same

Gas Law

Station 4:You Can Do it!• Instructions:  

– Place 5 ml of water in the can. Heat on hot plate until steam begins to escape then quickly place in the ice bath.

– Determine whether or not the pressure, volume, and temperature is increasing, decreasing or staying the same and record the data in your journal. 

– Write a paragraph to describe your observations.

Pressure Volume Temper-ature

Increase, decrease, same

Gas Law

Station 5: Balloon and the Flask (or Hot Air Ballooning)

• Instructions:– Pull a balloon over a flask with 5ml of water in it. – Place on a hot plate and observe the balloon.– Determine whether or not the pressure, volume, and temperature is

increasing, decreasing or staying the same and record the data in your journal. – Write a paragraph to describe your observations.

Pressure Volume Temper-ature

Increase, decrease, same

Gas Law

Station 6: Balloon and the Flask (or Hot Air Ballooning)

• Instructions:– Pull a balloon over a flask with 5ml of water in it. – Place in an ice bath and observe the balloon.– Determine whether or not the pressure, volume, and temperature is

increasing, decreasing or staying the same and record the data in your journal. – Write a paragraph to describe your observations.

Pressure Volume Temper-ature

Increase, decrease, same

Gas Law

Station 7  Super Duster & Office Buster• Instructions:

– Wrap your hand around one of the duster cans. Make sure your palm is in complete contact with the can. Now, depress the nozzle.

– Determine whether or not the pressure, volume, and temperature is increasing, decreasing or staying the same and record the data in your journal.

– Write a paragraph to describe your observations.

Pressure Volume Temper-ature

Increase, decrease, same

Gas Law

Station 8: Balloon in a bottle!• Instructions:  

– Start the paper on fire and carefully drop it into the flask. Quickly place the water balloon on top and observe. Use the straw to help remove the balloon.

– Determine whether or not the pressure, volume, and temperature is increasing, decreasing or staying the same and record the data in your journal. 

– Write a paragraph to describe your observations.

Pressure Volume Temper-ature

Increase, decrease, same

Gas Law

Rising Water

• Why did the green water rise in the graduated cylinder after the candle flame went out?

• What happened to the temp inside the graduated cylinder because of the flame?

• How did that affect the volume?• After the flame went out the temp ____?• The volume of the gas in the graduated cylinder ______?• This resulted in a decrease in the ________ inside the

graduated cylinder.• The pressure (atmospheric) on the water in the pan was

greater and that forced the water to rise in the cylinder.