Teacher Notes
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Wind BagDemonstration Kit
Publication No. 12951
IntroductionA wind bag is like a balloon without any elastic qualities. It’s made out of material that is similar to a plastic grocery bag. It is eight feet long and ten inches in diameter. How many breaths would it take to blow up a bag of this size? 10... 20... 30... more? With a little practice you will be able to blow up the bag in one breath. Try these two exciting activities with your wind bags. Concepts
MaterialsBig breath of air
Ruler:Scissors Tables, identical, flat, 4–6 feet in length, 2 Wind bags, 4 Safety PrecautionsWarn students to be careful when turning, lifting and lowering tables. Warn them to not get their fingers caught between the tables. Follow all normal laboratory guidelines. Have at least one adult volunteer near the table in case the tap table starts to move. ProcedureActivity 1
Correlation to Next Generation Science Standards (NGSS)†Science & Engineering PracticesAsking questions and defining problemsDeveloping and using models Planning and carrying out investigations Constructing explanations and designing solutions Disciplinary Core IdeasMS-PS2.A: Forces and MotionMS-PS2.B: Types of Interactions MS-PS3.B: Conservation of Energy and Energy Transfer MS-PS3.C: Relationship between Energy and Forces HS-PS2.A: Forces and Motion HS-PS2.B: Types of Interactions HS-PS3.B: Conservation of Energy and Energy Transfer HS-PS3.C: Relationship between Energy and Forces Crosscutting ConceptsPatternsCause and effect Scale, proportion, and quantity Systems and system models Energy and matter Performance ExpectationsMS-PS2-2. Plan an investigation to provide evidence that the change in an object’s motion depends on the sum of the forces on the object and the mass of the object DiscussionActivity 1 {12951_Discussion_Image_1}
Activity 2 Air from the students’ lungs is being forced into the plastic bag. The air is not allowed to escape because the students are holding the bag shut between breaths. The compressed air is exerting air pressure in all directions. As the bags expand, air pressure is causing the inverted table to rise. Every student in the class can do a small scale version of this experiment by putting a ten-inch-long party balloon under a heavy book. Air pressure is used to inflate bicycle, car and truck tires. Air safety bags in cars are another practical application of this scientific principle. A typical application of Pascal’s principle for gases and liquids is the automobile lift seen in many service stations and garages. Compressed air exerts pressure on the oil in an underground reservoir. The oil in turn transmits the pressure to a cylinder, which lifts the automobile. ReferencesSpecial thanks to John Mauch, Steve Spangler and Tom Gilmore for providing us with this activity. |