New
New
Year 10
OCR
Higher

Measuring density

I can measure the density of solids and liquids.

New
New
Year 10
OCR
Higher

Measuring density

I can measure the density of solids and liquids.

Lesson details

Key learning points

  1. Density is calculated using the equation: density = mass ÷ volume.
  2. The volume of water displaced by a submerged object is equal to the volume of the object.
  3. The dimensions of a regular cuboid can be measured accurately with Vernier callipers.
  4. The volume of a regular cuboid is calculated using the equation: volume = length × width × height.

Common misconception

Pupils confuse the mass or weight of an object with density.

Provide pupils with a range of objects of varying sizes that they are going to measure the density of. Before measuring density, ask the pupils to rank the objects in order of density with explanations. Compare results to the list after measurements.

Keywords

  • Density - The mass per cubic metre (m³) or cubic centimetre (cm³) of a material.

  • Displacement can - A can with a spout used to measure the volume of a submerged object.

  • Vernier callipers - A device used to measure length precisely.

  • Micrometer - A device to measure length to very high precision.

Digital callipers will make length measurements much easier for many pupils. Coloured water also makes volume measurements easier.
Teacher tip

Content guidance

  • Risk assessment required - equipment

Supervision

Adult supervision required

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
Which of the following are units of density?
grams per square centimetre (g/cm²)
Correct answer: grams per cubic centimetre (g/cm³)
kilograms per square metre (kg/m²)
Correct answer: kilograms per cubic metre (kg/m³)
Q2.
A solid object is placed in some water in a container. Which of the following statements are correct?
If the object has less mass than the water, it will float.
If the object has less volume than the water, it will float.
Correct answer: If the object is less dense than the water, it will float.
If the object has more mass than the water, it will float.
If the object is denser than the water, it will float.
Q3.
Sort the following measuring instruments into order of increasing precision, starting with the one that is least precise.
1 - metre ruler without millimetre markings
2 - 30 cm ruler with millimetre markings
3 - Vernier callipers
4 - micrometer
Q4.
The length, width and height of a cuboid are 2.0 cm, 4.0 cm and 6.0 cm respectively, and the mass is 170 g. The density of the cuboid is g/cm³. Give your answer to 2 sig. figs.
Correct Answer: 3.5
Q5.
Which of the following statements are correct?
Correct answer: The mass of a solid copper block depends on the block’s volume.
The density of a solid copper block depends on the block’s volume.
A 3 kg block of pure gold is denser than a 2 kg block of pure gold.
Correct answer: A 3 kg block of pure gold has greater volume than a 2 kg block of pure gold.
Q6.
Two objects, P and Q, have equal mass. The volume of Q is twice the volume of P. Which of the following statements is correct?
Q has the same density as P.
Correct answer: Q has half the density of P.
Q has twice the density of P.

6 Questions

Q1.
Match each type of sample to the most suitable piece of equipment to measure its volume.
Correct Answer:a small cube,Vernier callipers

Vernier callipers

Correct Answer:a key,displacement can and measuring cylinder

displacement can and measuring cylinder

Correct Answer:a few millilitres of oil,measuring cylinder only

measuring cylinder only

Q2.
Sort the following steps in the correct order to describe how to measure an object’s volume using a displacement can.
1 - Fill a displacement can with water until it is just below the spout.
2 - Place an empty measuring cylinder under the spout.
3 - Place the object in the displacement can.
4 - Wait for water to finish pouring from the spout.
5 - Measure the volume of water in the measuring cylinder.
Q3.
A measuring cylinder has mass 80.2 g. When 32 ml, which is the same as 32 cm³, of a liquid is added to the cylinder, the total mass is 342.6 g. The density of the liquid is g/cm³.
Correct Answer: 8.2, 8.20
Q4.
A pupil measures an object’s volume by placing it in water in a measuring cylinder, and then measures its mass. Which of the following will make the calculated density higher than the real density?
Measuring the mass of the object when it is dry.
Correct answer: Measuring the mass of the object when it is wet.
Forgetting to subtract the volume of water from the volume of object + water.
Measuring water volume, then spilling some water while putting the object in.
Q5.
The volume of a sphere can be calculated using the formula $$V=\frac{4}{3}πr^3$$, where $$r$$ is the radius. A solid sphere has radius 5.50 cm and mass 6760 g. What is the density of the sphere?
0.553 g/cm³
5.50 g/cm³
Correct answer: 9.70 g/cm³
29.3 g/cm³
293 g/cm³
Q6.
When an object is placed in a displacement can, it displaces 139 cm³ of water. The mass of the object is 0.85 kg. What is the density of the object in kilograms per cubic metre, to 2 sig. figs.?
0.61 kg/m³
6.1 kg/m³
160 kg/m³
1600 kg/m³
Correct answer: 6100 kg/m³

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