1. Chapter 11 Section 4: Bernoulli’s Principle
Key Concepts: According to Bernoulli’s principle, how is fluid pressure related to the motion of a fluid? What are some applications of Bernoulli’s principle?
Key terms: Bernoulli’s principle, lift

3. Pressure and moving fluids
Fluid motion
A fluid naturally flows from an area of high pressure to low pressure (important)
Bernoulli’s principle
In the 1700s, Swiss scientist Bernoulli discovered
The faster a fluid moves, the less pressure it exerts.

4. Applying Bernoulli’s Principle
Bernoulli’s principle helps explain how planes fly, why smoke rises up a chimney, and how a flying disk glides through the air.

5. Objects in flight
Bernoulli’s principle with air – if the air moves faster above the object, fluid pressure pushes the object upward. If the air moves faster below the object, fluid pressure pushes it downward. Wings of airplanes are designed to produce lift – an upward force. Look at figure 18 on page 395.

6. Atomizers Perfume atomizers (spray things)
When you squeeze a rubber bulb, air moves quickly past the top of the tube. Moving air lowers pressure at the top of the tube. Greater pressure in the flask pushes the liquid up into the tube.

7. Chimneys
Smoke rises because hot air rises, and partly because it is pushed. Wind blowing across the top of a chimney lowers the air pressure there. Higher pressure at the bottom pushes air up.

8. Flying disks
Upper surface is curved like an airplane. Faster moving air following the disk’s curved upper surface exerts less pressure than the slower moving air beneath. A net force acts upward.