Pascal & Bernoulli

Page 90

Pascal

Movement of sea star is caused by pressure changes in fluid tubes within its body

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Transmitting Pressure

1600’s French Scientist Blaise Pascal studied fluid pressure

What happens when you press on a closed bottle?

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Pascal’s Principle

When a force is applied to a confined liquid, the change in pressure transmitted equally to all parts of the fluid

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Hydraulic Systems

Closed fluid system to take advantage of Pascal’s principle

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Hydraulic Systems

How does the force applied match the force transmitted?

Same

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Hydraulic Systems

System B (larger side in 20 X)

20 X more force

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Hydraulic Systems

How?

Uses fluid to transmit pressure equally

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Hydraulic Systems

Car Breaks

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Review

What is Pascal’s principle?

What is the device that uses this system?

Hydraulic System

What is the force? F = Pressure x Area

If pressure is 2 Pa and area is 10 m2

F = 2 Pa x 10 m2

F = 20 N

Bernoulli’s Principle

1700’s Swiss Scientist Daniel Bernoulli

Principle = As the speed of a moving fluid increases, the pressure within the fluid decreases

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Paper

Take a sheet of paper and hold the corners.

Blow across the top of the paper

What happens?

Why?

Air pressure below is

higher so it pushes the

paper up

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Ca ns

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Applying Bernoulli

Objects are designed so that the change shape causes a change speed of air

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Applying Bernoulli

If air moves faster above, how does the object move?

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Applying Bernoulli

If air moves faster below, how does the object move?

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Applying Bernoulli

Draw the air flow of a wing.

Air moving over the top exerts less …

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Applying Bernoulli

Lift is another term for upward force

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Chimneys

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Atomizers

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Flying Discs

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Bat Wings

Read story

1. What would a bat use to land? Why?

2. Which would the bat use to catch bugs? Why?

3. Average flying? Why?

4. What would happen if one wing a and the other c? Why?

5. Why never use d?