Science Review 4-6

Question 1

Viscosity

Answer 1

Describes the thickness of a fluid

A thicker liquid is more viscous and has a high viscosity

Question 2

Flow Rate

Answer 2

Measures the amount of fluid that passes a point in a certain amount of time (speed).

Question 3

Density

Answer 3

Measures the mass per unit of volume for a substance.

Question 4

Mass

Answer 4

Mass is the amount of matter in a sample. It is like
the amount of particles in it. Measured in g

Lots of particles (high mass) in a small volume
means that a substance has a high density. Few particles (low mass) in a large volume means
that a substance has a low density.

Question 5

Volume

Answer 5

Volume is the amount of three-dimensional space

that something occupies. Measured in mL

Question 6

Buoyancy

Answer 6

the tendency for materials to rise or float in a fluid.

• if something is floating, it has positive buoyancy
• if something is sinking, it has negative buoyancy
• objects that neither sink or float have neutral buoyancy

Question 7

Archimedes Principle

Answer 7

The weight of the water displaced equal to the weight of the object means that an object will float.

Question 8

Friction

Answer 8

Force resulting when 2 objects touch or rub together.
The force resulting from the particles touching is called internal friction. When movement is slowed due to internal friction we say they have resistance to flow.

Question 9

Which state has the most resistance due to friction?

Answer 9

Solids - Particles are closer together meaning more friction.

Question 10

Increased viscosity means:

Answer 10

Increased friction between particles
Increased resistance to flow
Decreased flow rate

Question 11

How does temperature affect viscosity?

Answer 11

When particles heat up, they speed up, therefore, increasing friction between particles meaning the viscosity will increase.

Question 12

How does temperature affect the flow rate in liquids and gasses?

Answer 12

Liquids – the higher the temperature the more easily
the particles slide past each other, the faster the flow
rate
Gases – the higher the temperature the more collisions
between gas particles, the slower the flow rate

Question 13

Does liquid water or water vapour have

a greater density?

Answer 13

Liquid water is denser than water vapour because
the particles in a liquid are closer together than the
particles of a gas so in the same sized area there will be
more particles of liquid water than particles of water
vapour!

Question 14

The formula for density is:

Answer 14

D = m/v

Question 15

Buoyant Force

Answer 15

The force of the moving particles in a fluid that are pushing up on the object.

• high density means that here are more particles to push up and increase buoyancy
• low density means that there are fewer particles to push up and increase buoyancy

Question 16

Average density

Answer 16

Average density is the total mass of an object divided by its total volume.

• a life jacket which is filled with air will lower a person’s average density, enabling the person to float
• holding a metal boat anchor will increase your average density, causing you to sink

Question 17

Why buoyant force is often called the “anti-gravity” force. What causes buoyant force?

Answer 17

Buoyant force is working against gravity. Gravity pushes downwards.

It comes from particle density.

Question 18

Describe the relationship between solubility, density and buoyancy.

Answer 18

When something is soluble in water, the amount of particles in the water will increase. This means that the water will be more dense and the buoyant force will be stronger.

Question 19

Explain how a fish uses its swim bladder to make itself positively buoyant, neutrally buoyant and negatively buoyant.

Answer 19

When the swim bladder expands, it increases in volume and displaces more water meaning that the fish’s buoyancy will increase making it float. When the fish’s swim bladder deflates, the fishes buoyancy will decrease meaning that the fish will sink.

Question 20

What happens to density when mass increases while volume stays the same?

Answer 20

It’s density will become greater

Question 21

What happens to density when volume increases while mass stays the same?

Answer 21

The density will decrease