Lesson Plan : Can you take the Pressure

Teacher Name:
 Kim Ritchie
 Grade 3

 Relationship between air pressure and the velocity of moving air.
 Air Pressure: The force exerted by air on an area (metric: N/m2, English: lbs/in2). Bernoulli's Principle: The law that pressure exerted by a fluid decreases as the rate of flow increases. Force: A push or pull on an object. Lift: The force resulting from the difference in air pressure above and below the wings that causes the aircraft to move upwards. Fluid: Any substance where the molecules can move around feely. A fluid is any gas or liquid.
 This lesson introduces students to the concept of air pressure. Students will explore how air pressure creates force on an object. They will study the relationship between air pressure and the velocity of moving air.
 Understand that air pressure decreases as the speed of air increases. Understand that air pressure acts in all directions (not just down).
 1 sheet of paper (new or recycled) 2 round balloons 2 pieces of string (18 inches long) 2 small plastic cups 2 straws 1 ping pong ball Water
 Aske the students "what is air?" Then have the blow into their hand. Then answer what air is.(a collection of molecules � very small particles that we cannot see � that cover the surface of the Earth. Air is comprised of 78% Nitrogen, 21% Oxygen, and the remaining 1% is mostly argon and carbon dioxide.)
 Part A. Have the students fold a piece of paper (lengthwise) in half and make a paper tent. Ask the students to predict what will happen when they blow into the tent. Will it appear to get larger, will it remain unchanged, or will it bend down toward the table?(Alternately, have students turn their paper tents upside down and blow through the V shaped paper.) Make sure the students notice that the tent flattens. This is because the air moving through the inverted V has less pressure, so the higher pressure on the outside of the paper tent flattens the paper. Have the students experiment with their paper tents, answer the relevant worksheet questions, and discuss their results. Part B Blow up two balloons. Tie them off, and then attach a string to each one. Have students hold the two balloons together. Ask them to predict what will happen when they blow between the two balloons. Student should record their hypothesis in the space provided on the worksheet. Have students hold the balloons 4-6 inches apart and blow between them. If the students hold the balloons too close together, the balloons will simply move away from the student. The balloons must be sufficiently far apart so that students can blow between the balloons, not at the balloons. The students should see the balloons come together just `bnnbNB like the paper V in Part A of the Procedures section.
Checking For Understanding:
 Have the students record measurements and follow along with the activity on their worksheet. After students have finished their worksheet, have them compare answers with their peers. Discuss as a class.
 Have the students engage in open discussion to suggest solutions to the following problem: Given what we have learned, how does the Bernoulli Principle relate to airplane flight? (Answer: If air moves faster on one side of an object, the air pressure decreases and the object will move in the direction of the faster moving air. This is how wings create lift and why the objects in this experiment move in the direction of the faster air.) Activity Extensions (Return to Contents)
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