Physics 1090
12-2-09
Labor 3
Description
The objective I chose for this labor was the last objective for Unit 4: Describe the change in volume of a gas in response to a change in pressure. As pressure increases, the volume of a gas decreases. The diver activity we did in class is an excellent demonstration of this concept because it allows students to see the air bubble being compressed as the diver sinks.
Implementation
This activity should be done in a traditional classroom setting with teacher direction and student experimentation because the teacher would be able to monitor and guide the student’s to the correct conclusion and explanation and would probably work best with older students in 4th-6th grades. It could be incorporated into a unit discussing states and properties of matter or a unit discussing fluids. Prior to implementing the diver activity, students should know the states of matter and how the molecules of each state act (i.e. solid molecules are tightly packed together, liquid molecules are loosely together, gas molecules are extremely loose and movable.) Knowing the formation of molecules in a gas state will help students understand the effects of increasing pressure on the volume of a gas.
To begin the activity, I would have three or four bottles with inverted test tubes (divers) already set up to be sure the test tubes have different air bubble sizes. I would ask the students to explain why the test tube divers are floating and what they think will happen when the bottles are squeezed. Then, the students will form groups around the divers, squeeze the bottles, and formulate explanations for what they observe. I would direct the students to observe the air bubble specifically by asking a question such as “What happens to the air bubble when the diver sinks?” The students could change groups to observe all of the divers, and continue observing and expanding their explanations. After the students have observed all of the divers, I would ask them to explain their observations, and guide them to concluding that the diver sinks because the increased pressure in the bottle compresses the air bubble inside the test tube.
Evaluation
The diver activity is an excellent tool for this objective because students can observe the air bubble being compressed as the pressure inside the bottle is increased. This activity also works with a ketchup or honey packet in place of the test tube; however, using a test tube allows students to actually see and measure the bubble being compressed. The materials necessary to create the diver are fairly inexpensive and provide a great activity to explain an interesting objective. An additional tool that would be useful is a picture or animation of what is happening to the molecules in a gas as it is being compressed which would help students see the volume being decreased. The reason I choose the diver activity as a tool for learning this objective is because it is a fun, hands-on activity that will spark the student’s interest more than sitting in their desks and reading about the same thing from a boring textbook.