Kinetic Theory Explains how particles in matter behave. 16-2

Section 2 Properties of Fluids

Objectives Explain Archimedes’ principle and buoyancy. Explain Bernoulli’s principle and identify how we use it. Explain Pascal’s principle. CLE 3202.1.8 Investigate the relationship among the pressure, temperature, and volume of gases and liquids.

Buoyancy – ability of a fluid (liquid or gas) to exert an upward force on an object immersed in it

https://www.youtube.com/watch?v=g6aErhwFXsg

An object in a fluid will float if its weight is equal to the buoyant force acting on it from the fluid. An object in a fluid will sink if its weight is more than the buoyant force acting on it from the fluid.

Archimedes’ principle – buoyant force on an object is equal to the weight of the fluid displaced by the object. An object will float if its density is less than the density of the fluid it is placed in.

Archimedes's Principle

Cont.

Pascal’s principle – pressure applied to a fluid is transmitted throughout the fluid (toothpaste)

Pressure is force exerted per unit area. Hydraulic machines use this principle to lift heavy loads.

Pascal’s Principle http://www.edumedia-sciences.com/en/a260-hydraulic-lift

Bernoulli’s principle – as the velocity of a fluid increases, the pressure exerted by the fluid decreases 1. Airplanes use this principle to fly.

Bernoulli’s Principle

Bernoulli’s Principle in Flight

Viscosity – a liquid’s resistance to flow Molecular structure determines a fluid’s viscosity Increased temperature will lower viscosity.

Discussion Question Why do some objects sink and other float in water?

Answer An object’s density and its weight determine whether it will float. Objects with density less than the density of water will float. Objects that weigh less than the buoyant force will float.

Objectives Explain Archimedes’ principle and buoyancy. Explain Bernoulli’s principle and identify how we use it. Explain Pascal’s principle. CLE 3202.1.8 Investigate the relationship among the pressure, temperature, and volume of gases and liquids.