1. Forces in Fluids
Chapter 11

2. Today we will…
Describe forces in fluids using Cornell Notes

3. 1. Pressure, floating, and sinking
2. Pressure – what is it? 3. Pressure = Force/area 3. The amount of pressure you exert depends on the area over which you exert a force. 3. Measured in Pascals (Pa) = N/m2 3. Use a barometer to measure atmospheric pressure 3. Discuss in your groups: Why do you sink in snow with boots, but barely sink in the snow with snowshoes?

4. 2. Fluid Pressure
3. Remember – a fluid is a material that can easily flow 3. Particles move in all directions 3. All of the forces exerted by the individual particles combine to make up the pressure exerted by the fluid. 3. Air fluid = atmospheric pressure

5. 3. Balanced pressure – air pressure is balanced on the Earth.
4. Discuss – what happens when it becomes unbalanced?
4. Atmospheric pressure decreases as your elevation increases
4. Atmospheric pressure increases as depth increases

6. 2. Floating or Sinking
3. Density – what is it? 4. Density = Mass/Volume 4. By comparing densities you can predict whether an object will float or sink in a fluid. 4. Changes in density will cause an object to sink – like the Titanic – or float like a beach ball. 5. Density explains how a submarine operates

7. 2. Buoyancy
3. Buoyant force – what is it? 4. Water and other fluids exert an upward force that acts on a submerged object 4. Acts in the direction opposite to the force of gravity so it makes an object feel lighter. 4. The less dense the object, the greater the buoyant force.

8. 3. If the weight of an object is a
3. If the weight of an object is a. greater than the buoyant force, it will sink b. Less than the buoyant force, it will float c. Equal to the buoyant force, it will not sink 3. Examples a. Jellyfish – floats b. Turtle – underwater but can float in place c. lobster – more density than water and unbalanced forces cause it to sink because they are greater than the buoyant force

9. Warm- up
You have 10 Minutes to complete these… Create a Vocab Map for the following terms: Pressure Density Buoyant Force

10. Today we will…
Compare and contrast Archimedes’, Pascal’s, and Bernoulli’s principles using demonstrations and Cornell Notes.

11. 1. Principles of Forces in Fluids
2. Archimedes’ principle 3. Ancient Greek Mathematician 3. Principle states that the buoyant force acting on a submerged object is equal to the weight of the volume of fluid displaced by the object. 3. Examples: 4. Ship’s hull vs Piece of steel the same weight

12. 2. Pascal’s Principle
3. Blaise Pascal in 1600’s 3. Principle States that when force is applied to a confined fluid, the change in pressure is transmitted equally to all parts of the fluid. 3. Example – Squeezing a water bottle

13. 2. Bernoulli’s Principle
3. Swiss Scientist in the 1700’s 3. Daniel Bernoulli 3. Principle states that as the speed of a moving fluid increases, the pressure exerted by the forces decreases. 3. Paper example

14. 3. Applying Bernoulli’s principle
4. Explains how planes fly 4. Flying Frisbees 4. Smoke from a chimney

15. Homework Concept Maps: Bernoulli’s principle Archimedes’ principle
Pascal’s principle