Lab Report # 4.2: Bernoulli's Principle
Materials:
- Balloon
- Hair Blower
- Drinking straw/cup of water
- Beach ball or balloon/stand fan
- Strip of Paper
- Balloon
- Hair Blower
- Drinking straw/cup of water
- Beach ball or balloon/stand fan
- Strip of Paper
Learning Station A: Kissing Balls
Blow at the middle of the two hanging balls. Observe what will happen.
Discussion:
1. How did the two balls react? Use an illustration.
- The balls moved together towards the center
Discussion:
1. How did the two balls react? Use an illustration.
- The balls moved together towards the center
2. At which side of the two balls is the velocity of the air greater?
- The velocity of the air is greatest at the side of the balls facing the opposite of the center
3.What does the behavior of the two balls suggest about the pressure between them and the pressure on either side?
- Bernoulli's Principle states that as velocity increases, pressure decreases. As air is blown between the two balls, the pressure at the center becomes lower. The higher pressure existing on the other side of the balls then pushes them towards the center.
- The velocity of the air is greatest at the side of the balls facing the opposite of the center
3.What does the behavior of the two balls suggest about the pressure between them and the pressure on either side?
- Bernoulli's Principle states that as velocity increases, pressure decreases. As air is blown between the two balls, the pressure at the center becomes lower. The higher pressure existing on the other side of the balls then pushes them towards the center.
Learning Station B
Hold one edge of the strip of paper. Blow the air above the loose end of the paper.
Discussion:
1. How does the paper react as you blow at its bottom? Use an illustration for pressure directions.
- When blown at the bottom, the loose end of the paper goes downward
Discussion:
1. How does the paper react as you blow at its bottom? Use an illustration for pressure directions.
- When blown at the bottom, the loose end of the paper goes downward
2. How do you explain your observation?
- As air is blown at the bottom of the paper, the pressure there becomes lower. The higher pressure at the top of the paper strip then pushes it downward.
- As air is blown at the bottom of the paper, the pressure there becomes lower. The higher pressure at the top of the paper strip then pushes it downward.
Learning Station C
Switch on the hair blower and place the balloon above the blower.
Discussion:
1. Why does the balloon tend to stay within the air column? Use the illustration to show the direction of the net pressure.
- Bernoulli's Principle states that the pressure decreases inside a stream of flowing air (in this case, the air from the hair blower). When the balloon begins to move out of this low pressure stream, the higher pressure of the air in the surroundings pushes it back into the moving stream.
Discussion:
1. Why does the balloon tend to stay within the air column? Use the illustration to show the direction of the net pressure.
- Bernoulli's Principle states that the pressure decreases inside a stream of flowing air (in this case, the air from the hair blower). When the balloon begins to move out of this low pressure stream, the higher pressure of the air in the surroundings pushes it back into the moving stream.
2. Why does this happen?
- Same explanation as No. 1. Bernoulli's Principle states that the pressure decreases inside a stream of flowing air (in this case, the air from the hair blower).
- Same explanation as No. 1. Bernoulli's Principle states that the pressure decreases inside a stream of flowing air (in this case, the air from the hair blower).
Learning Station D
Discussion:
1. What did you observe as you blow air through the vertical straw?
- After air was blown through the straw, the water rose through the drinking material.
2. How do you explain your observations?
- The pressure inside the straw is lowered by the moving air. Thus, the air pressure on the surface of the water in the glass becomes greater, and this forces the water up through the straw.
1. What did you observe as you blow air through the vertical straw?
- After air was blown through the straw, the water rose through the drinking material.
2. How do you explain your observations?
- The pressure inside the straw is lowered by the moving air. Thus, the air pressure on the surface of the water in the glass becomes greater, and this forces the water up through the straw.