Chapter 14, Section 2 Buoyant Force

1. Chapter 14, Section 2Buoyant Force

2. Buoyant Force • The upward force that fluids exert on all matter.

3. What causes it? • Fluids exerts pressure on all sides of an object. • There is more pressure on the bottom because pressure increases with depth. • The water exerts a netupwardforce.

4. Archimede’s Principle • The buoyant force on an object in fluid is an upward force equal to the weight of the fluid that the object displaces.

5. Weight - Sink or Float?? • If an object’s weight is greater than the buoyant force = sinks. • If an objects weight is equal or less than the buoyant force = floats

6. Buoying Up • Buoyed up means to push back up. • A duck’s weight is = to 9N. If it dives underwater, The duck will displace more than 9N of water. What will happen to the duck? • Answer: 9N

7. Density - Sink or Float? • If an object’s density is less than the density of water = floats. • If an object’s density is greater than the density of water = sinks.

8. Steel Ships • Steel is 8 times more dense than water, so how do steel ships float? • They’re shaped like a bowl to increase the volume of the ship and decrease its overall density.

9. More Dense Than Air • Most substances are more dense than air. • They contain more mass than an equal volume of air does. • So a rubber duck doesn’t float in air, but helium balloons do.

10. End of Ch.14-2