2. How Is Pressure Transmitted in a Fluid?

Oh! The Pressure Forces in Fluids

Key Questions: 1. What is pressure? 2. How is pressure transmitted in a fluid?

Materials: 2L soda bottle, balloon, straw, Bunsen burner, water, soda can, hot pad, goggles, test tube, plastic cup, index card.

Procedure: Part 1: Balloon in a Bottle 1. Take the balloon and place it inside of the 2 liter soda bottle with the open end facing out. Do not let the balloon drop into the soda bottle and DO NOT wrap the balloon around the mouth of the soda bottle. 2. Try to blow up the balloon. Can you blow it up? 3. Now insert a straw inside the bottle next to the balloon . Keep the straw sticking out of the container. Try to blow up the balloon, DO NOT blow on the straw.

Record in your notebook. 1. Draw the bottle and balloon with NO straw using force arrows. 2. Explain why you could not blow up the balloon in the bottle and then why you could with the straw. Use the word pressure in your explanation.

Part 2: Can crushing 4. Fill up the pie tin full with water and place ice cubes in the pie tin to make the water cold. 5. Put on safety goggles and use the hot pad. 6. Using your best judgement, fill the aluminum can about ¼ full of water. 7. Turn on Bunsen burners and using the tongs, place the aluminum can over the heat till the water comes to a boil and steam is coming out and most of the water has evaporated. 8. QUICKLY turn the can over so that the open hole is submerged into the cold ice water. Record what happened in data table.

Record in your notebook. 3. Draw the can and pie plate after you have turned it over using force arrows. 4. Explain why the can was crushed. Use the word pressure in your explanation.

Part 3: Cartesian Diver 9. Fill the bottle up with water until it almost overflows. Leave a very small amount of air space. 10. Take the test tube and fill it with some water. Place your thumb over the opening and quickly place it upside down into the soda bottle. 11. Twist on the cap and close it. Squeeze the bottle and observe what happens. Record observations. 12. Experiment with different amounts of water in the test tube. The best diver will be able to float and sink. Record in your notebook. 5. Draw the bottle and test tube when you squeezed and the diver sinks. Use force arrows. 6. When you exerted pressure on the bottle, how did it change the density of the diver? 7. Since the diver sinks when you press on the bottle, what does that mean about buoyant force?

Part 4. Card Trick 13. Fill a small plastic cup to the brim with water. 14. Gently place an index card over the top of the cup. 15. Hold the card in place and slowly turn the cup upside down, Let go of the card. 16. Without touching the card, turn the cup on its side.

Record in your notebook. 8. Draw the cup and card when it is upside down. Use force arrows. 9. What happened when you turn the cup on its side? Can you explain this? Use the word pressure in your explanation.

Conclusion Questions: 10.What is a fluid? 11.What is pressure? 12. How is pressure transmitted in a fluid? 13. How does the water pressure change in the bottle shown? How can you tell? 14.How does the air pressure change in the diagram? 15. Why is it harder to breath on top of mountain and easier to breathe at sea level?