8i Summary Sheet

Question 1

What is a fluid?

Answer 1

Fluids are liquids or gases.

Question 2

Give two properties of solids

Answer 2

● fixed volume
● fixed shape

Question 3

Give 2 properties of liquids

Answer 3

● fixed volume
● take shape of container

Question 4

Give two properties of gases

Answer 4

● expand to fill container
● take shape of container

Question 5

Which state of matter has the most energy?

Answer 5

Gas particles have the most energy

Question 6

What states of matter can be poured?

Answer 6

Gas and liquid

Question 7

What is density?

Answer 7

Density is the mass of a certain volume of something.

Question 8

What is the formula for density?

Answer 8

Mass
Density=—————
Volume

Question 9

What are the 2 units for density.

Answer 9

The units for density are g/cm^3 or kg/m^3

Question 10

What are the 2 units for density.

Answer 10

The units for density are g/cm^3 or kg/m^3

Question 11

When do substances change state?

Answer 11

Substances can change state when they are heated or cooled.

Question 12

Does the temperature of a substance change while it is melting?

Answer 12

The temperature of a substance does not change while it is melting, even if it is still being heated.

Question 13

What happens to substances when they are heated?

Answer 13

Substances expand when they are heated.

Question 14

Order the states of matter from taking up the most space to the least.

Answer 14

The particles in a solid vibrate more and take up less space. The particles in liquids and gases move around faster and take up more space.
Gas > liquid > Solid

Question 15

1) Why do substances contract when they cool down?
2) What happens to the volume and density?

Answer 15

1) Substances contract when they cool down, as the particles have less energy and do not move as
much.
2) This reduces the volume and increases the density.

Question 16

Can fluids flow?

Answer 16

Yes

Question 17

Can fluids flow?

Answer 17

Yes

Question 18

What direction does pressure in fluids act?

Answer 18

Pressure in fluids acts in all directions.

Question 19

Why is there pressure in fluids?

Answer 19

The particles in fluids are moving all the time and hitting the walls of containers and other things they come into contact with. The force of the collisions causes pressure, which acts in all directions.

Question 20

Give 3 ways pressure of gas in a container can be increased.

Answer 20

● putting more particles into the container (so there will be more collisions with the container
walls each second).
● heating the gas (so the particles move faster, hitting the walls harder and more often).
● reducing the volume of the container (so the particles do not have as far to go between the
walls and so collide with the walls more often).

Question 21

What happens to the pressure when you go deep in the sea vs high on a mountain?

Answer 21

As you go deeper into the sea, pressure increases because there is more water above you
pressing down. If you climb a high mountain, the air pressure on you will get less, because there is
less air above you pressing down

Question 22

What does the weight of an object have to be for it to float on water and why.

Answer 22

The density of water is 1 g/cm^3, so objects with densities less than 1 g/cm^3 will float in water.

Question 23

What is drag?

Answer 23

Drag is another name for air resistance or water resistance.

Question 24

How can the amount of drag on something be reduced?

Answer 24

The amount of drag on something can be reduced by giving it a smooth surface and a streamlined shape.

Question 25

How can the amount of drag on something be reduced?

Answer 25

The amount of drag on something can be reduced by giving it a smooth surface and a streamlined shape.

Question 26

What happens to drag as the speed increases?

Answer 26

The drag increases as the speed increases.

Question 27

Why do objects moving through air get hot?

Answer 27

The particles transfer energy to the object, which is why objects moving through air can get hot.