Density

A student investigated how the density of a liquid affects the position of a wooden block floating in the liquid.

Figure 18 shows the apparatus.

This is the method used.

1. Put the wooden block in the beaker of liquid.

2. Allow the wooden block to come to rest so that it is floating in the liquid.

3. Measure the distance between the liquid surface and the bottom of the block.

4. Repeat steps 1 to 3 with liquids of different densities.

Give the independent variable in the investigation.

Give one control variable for the investigation.

Give one possible source of error when the student measured the distance between the liquid surface and the bottom of the block.

Table 6 shows the results.

Give one conclusion from the results.

Use the Physics Equations Sheet to answer questions 08.5 and 08.6.

Which equation links density (ρ), mass (m) and volume (V)?

Tick (✓) one box.

ρ = m × V

ρ = m × V³

The density of the wooden block was 0.85 g/cm³.

The mass of the wooden block was 30.6 g.

Calculate the volume of the wooden block in cm³.

Liquid C is water.

When liquid water is heated to its boiling point the water changes state.

What happens to the density of the liquid water as it changes state?

Tick (✓) one box.

The density decreases

The density stays the same

The density increases

Give a reason for your answer.

A student investigated how the density of a liquid affects the position of a wooden block floating in the liquid.

Figure 4 shows the apparatus.

This is the method used.

1. Put the wooden block in the beaker of liquid.

2. Allow the wooden block to come to rest so that it is floating in the liquid.

3. Measure the distance between the liquid surface and the bottom of the block.

4. Repeat steps 1 to 3 with liquids of different densities.

Give the independent variable in the investigation.

Give one control variable for the investigation.

Give one possible source of error when the student measured the distance between the liquid surface and the bottom of the block.

Table 2 shows the results.

Give one conclusion from the results.

Use the Physics Equations Sheet to answer questions 02.5 and 02.6.

Which equation links density (ρ), mass (m) and volume (V)?

Tick (✓) one box.

ρ = m × V

ρ = m × V³

The density of the wooden block was 0.85 g/cm³.

The mass of the wooden block was 30.6 g.

Calculate the volume of the wooden block in cm³.

Liquid C is water.

When liquid water is heated to its boiling point the water changes state.

What happens to the density of the liquid water as it changes state?

Tick (✓) one box.

The density decreases

The density stays the same

The density increases

Give a reason for your answer.

A student investigated the mass, volume and density of some solid metal cubes.

Figure 2 shows one of the cubes. The length of one side is shown.

Name a piece of equipment the student could use to measure the length of one side of the cube.

What is the volume of the cube in Figure 2 ?

Tick (✓) one box.

6.0 cm³

9.0 cm³

27.0 cm³

54.0 cm³

A different cube has a mass of 13 g.

The volume of this cube is 8.0 cm³.

Calculate the density of the cube.

Use the equation:

Give your answer to 2 significant figures.

Density (2 significant figures) = g/cm³ _________________

The student also investigated the density of a key.

Figure 3 shows the key.

Which piece of equipment could be used to measure the mass of the key?

Tick (✓) one box.

Balance

Stopwatch

Thermometer

Figure 4 shows a measuring cylinder containing water.

Describe how the equipment in Figure 4 could be used to measure the volume of the key.

Keys are usually made from metal.

Figure 3 shows a metal key.

Describe a method to determine the density of the metal the key is made from.

You should include the measuring instruments you would use.

Use the Physics Equations Sheet.

Figure 12 shows some of the processes in the water cycle.

Name process A and process B.

shows the locations of fresh water on Earth.

Calculate the amount of fresh water in lakes as a percentage of the total amount of fresh water.

Give two ways humans pollute the water in lakes.

Do not refer to litter, plastic pollution or rubbish.

The surface of a lake can freeze if the water at the surface of the lake cools to 0 °C.

Figure 14 shows the temperature of the water at increasing depth in a lake in winter.

Suggest why organisms in the lake can survive in winter.

Use Figure 14.

The middle layer of water is from 7 metres below the surface to 15 metres below the surface.

The temperature at a depth of 7 metres below the surface is 0 °C.

Determine the change in temperature per metre in the middle layer of water.

Use the equation:

Write down the equation which links density (ρ), mass (m) and volume (V).

The density of ice is 920 kg/m³.

Calculate the volume of 2.3 kg of ice.

Volume = m³ __________________

Describe a method to measure the mass and volume of a liquid.

Figure 3 shows some of the processes in the water cycle.

Name process A and process B.

2 Figure 4 shows the locations of fresh water on Earth.

Calculate the amount of fresh water in lakes as a percentage of the total amount of fresh water.

Give two ways humans pollute the water in lakes.

Do not refer to litter, plastic pollution or rubbish.

The surface of a lake can freeze if the water at the surface of the lake cools to 0 °C.

Figure 5 shows the temperature of the water at increasing depth in a lake in winter.

Suggest why organisms in the lake can survive in winter.

Use Figure 5.

The middle layer of water is from 7 metres below the surface to 15 metres below the surface.

The temperature at a depth of 7 metres below the surface is 0 °C.

Determine the change in temperature per metre in the middle layer of water.

Use the equation:

Write down the equation which links density (ρ), mass (m) and volume (V).

The density of ice is 920 kg/m³.

Calculate the volume of 2.3 kg of ice.

Volume = m³ __________________

Describe a method to measure the mass and volume of a liquid.