Fluids - Introduction

What are fluids?

• Liquids and gases are examples of fluids.

• Particles in a fluid can move past each other.

• Fluids exert pressure (push) evenly in all directions.

Multiple Choice

The term fluids generally applies to:

• solids and liquids

• liquids and gases

• solids and plasma

• solids and gases

Multiple Choice

If an object sinks in a fluid, _____.

• fluid density is greater than object density

• fluid density less than object density

• fluid density = object density

• density has nothing to do with object sinking or floating,

  only which state of matter the object is

Multiple Choice

If two objects have the same volume but one has a greater mass, the one with greater mass 

• Has a lower density
•  Has a higher density
• Will float
• Will sink 

Multiple Choice

If an object has a density of 3.6 g/mL and you put it into water (density =1.0g/mL,) will it sink or float?

• sink

• float

• partially sink

• partially float

Buoyant Force

• Buoyant force is the upward force that keeps an object immersed in or floating on a fluid.

• Archimedes' principle is used to find buoyant force. Archimedes' principle states

  "Buoyant force in a fluid is upward and = to weight of the fluid that the object displaces."

Multiple Choice

The upward force exerted by a fluid is called the...

• buoyancy force

• density force

• fluidity force

• normal force

What is pressure?

• Pressure is the amount of force exerted on a given area surface.

• As you pump more air into the tire, the pressure inside the tire increases. Why?

When you add air to a tire, you are pushing air into the tire. Inside the tire, the air molecules push against each other and against the walls of the tire.

Calculating pressure

• The SI unit of pressure is the PascalS (Pa)

• You calculate pressure by dividing the force by the area over which the force acts.

Pascal's Principle

• States that if the pressure in a container is increased at any point, the pressure increases at all points by the same amount (force evenly applied

Multiple Choice

When you increase your depth under water, the water pressure on your body

• increases

• decreases

• stays the same

Multiple Choice

What do we call the the amount of force exerted on a certain area?

• fluid

• pressure

• buoyant force

• normal force

Multiple Choice

A buoyant force is an upward force applied on an object by a 

• Substance
• Fluid
• Pressure
• Displacement

Multiple Choice

Pressure is measured in what units

• Newtons
• m/s
• Pascals
• Moles

Viscosity

• Viscosity is a liquid's resistance to flow and it depends on the particles attracton.

• The stronger the attraction between a liquid's particles, the more viscous the liquid is.

• Example: Honey flows more slowly than lemonade because honey has a higher viscosity than lemonade.

Multiple Choice

What is viscosity?

• A liquid's resistance to flow.
• a liquids flow.
• a liquid
• gas to solid.

Multiple Choice

High viscosity can be described as...

• a liquid that flows quickly

• a liquid that flows slowly

Multiple Choice

Peanut butter is an example of a...

• High viscosity liquid

• Low viscosity liquid

• Isnt a liquid at all! Don't be silly.

Multiple Choice

Low viscosity can be described as...

• liquids that flow quickly

• liquids that flow slowly

Multiple Choice

Viscosity can be described as...

• a physical property of liquids

• a physical property of solids

• a chemical property of liquids

Fluids in Motion

• Fluids in motion have some properties in common.

• Fluids move faster through small areas than through larger areas, if the overall flow rate remains the same.

• But fluids also vary in the rate at which they flow.