AQA GCSE Combined Science: Trilogy Physics Paper 1 (Foundation), November 2021: Question 1

13 marks · Low Demand difficulty · Short Answer

Investigate and determine the density of different types of rock, calculate density, plot a bar chart, and identify particle arrangement.

Practise this question

Question

Question 01 showing an investigation into the density of rocks. Figure 1 shows a piece of irregular limestone rock. Figure 2 shows equipment: a displacement can, measuring cylinders, and a beaker. Part 01.3 gives mass as 155 g and volume as 62 cm³ to calculate density using density = mass / volume. Figure 3 shows a bar chart of rock density for Basalt (3.0), Granite (2.75), Obsidian (2.4), and Pumice (0.25 g/cm³). Parts 01.8 and 01.9 ask about the particle arrangement of air and its effect on pumice density.
Question text

01 A student investigated the density of different types of rock.

Figure 1 shows a piece of limestone.

Figure 1

01.1 The student was not able to calculate the volume of the piece of limestone using

measurements taken with a ruler.

What is the reason?

[1 mark]

Tick ( ) one box.

A ruler is not very accurate.

The piece of limestone has an irregular shape.

There is a large uncertainty when using a ruler.4

01.2 Figure 2 shows some of the equipment given to the student.

Figure 2

Describe a method the student could use to determine the volume of the piece

of limestone.

*03* [4 marks]

01.3 The mass of the piece of limestone was 155 g.

The volume of the piece of limestone was 62 cm3.

Calculate the density of the piece of limestone.

Use the equation:

mass

density =

volume

[2 marks]

Density = g/cm3

Density can be measured in g/cm3.

01.4

What is another unit for density?

[1 mark]

Tick ( ) one box.

cm/g3

kg/m3

kg3/m

kg3/cm 6

Figure 3 gives the density of some other types of rock.

Figure 3

The student has a sample of an unknown type of rock.

The density of this rock is 2.4 g/cm3.

01.5 Draw a bar on Figure 3 to show the density of the unknown type of rock.

[1 mark]

01.6 Complete the sentence.

Choose the answer from the box.

[1 mark]

basalt granite obsidian pumice

The data in Figure 3 suggests that the unknown type of

rock is 7 .

01.7 The student cannot be certain that the unknown type of rock is one of the types of

rock in Figure 3.

Give a reason why.

[1 mark]

Pumice is a type of rock that has holes in it. The holes contain air.

01.8 Which diagram shows the arrangement of particles in air?

[1 mark]

Tick ( ) one box.

01.9 Complete the sentence.

Choose the answer from the box.

[1 mark]

less than the same as more than

The holes containing air cause the density of pumice to

be the density of other types of rock.

Mark scheme

Show the mark scheme Mark scheme for question 01 containing parts 01.1 to 01.9. 01.1 accepts 'the piece of limestone has an irregular shape' (1 mark). 01.2 provides a level 2 (3-4 marks) and level 1 (1-2 marks) descriptor for describing displacement can method to measure rock volume. 01.3 awards 2 marks for 155 / 62 = 2.5 g/cm³. 01.4 gives kg/m³ (1 mark). 01.5 awards 1 mark for drawing a bar at 2.4 g/cm³. 01.6 gives obsidian (1 mark). 01.7 gives 'other types of rock may have the same density as obsidian' (1 mark). 01.8 identifies the 4th diagram with widely spaced particles for air (1 mark). 01.9 gives 'less than' (1 mark). Total: 13 marks.

AO /

Question Answers Extra information Mark

Spec. Ref.

01.1 the piece of limestone has an 1 AO1

irregular shape 6.3.1.1

RPA17

01.2 Level 2: The method would lead to the production of a valid 3–4 AO1

outcome. The key steps are identified and logically sequenced. 6.3.1.1

RPA17

Level 1: The method would not lead to a valid outcome. Some 1–2

relevant steps are identified, but links are not made clear.

No relevant content 0

Indicative content

• add water to the displacement can until level with the spout

• place the limestone in the water

• avoid splashing water out of the displacement can

• collect the displaced water in the beaker or measuring cylinder

• measure the volume of the displaced water

• using a measuring cylinder

OR

• use the large measuring cylinder

• part fill the measuring cylinder water

• measure the initial volume on the measuring cylinder

• submerge the limestone in the water

• measure the final volume on the measuring cylinder

• volume of limestone = final volume − initial volume

To access level 2 the answer must refer to submerging the

limestone in water and using the measuring cylinder.

density =

01.3 62 2 AO2

density = 2.5 (g/cm3) 6.3.1.1

– COMBINED SCIENCE: TRILOGY – – RPA17

01.4 kg/m3 1 AO1

6.3.1.1

RPA17

01.5 bar drawn to 2.4 g/cm 1 AO2

6.3.1.1

RPA17

01.6 obsidian 1 AO3

6.3.1.1

RPA17

01.7 other types of rock may have allow not all rock types are 1 AO3

the same density as obsidian plotted on the bar chart 6.3.1.1

RPA17

01.8 4th box ticked 1 AO1

6.3.1.1

01.9 less than 1 AO3

6.3.1.1

Total 13

How to answer it

Density & Particle Model: Investigating Types of Rock

📋 WHAT THIS QUESTION TESTS

AQA Required Practical 5 (Density of Irregular Solids) & Particle Model of Matter:

  • Understanding why irregular solids cannot be measured with a standard ruler.
  • Writing a clear, sequential step-by-step method using a displacement (Eureka) can or measuring cylinder.
  • Applying the density equation: density = mass ÷ volume .
  • Knowledge of standard SI units of density ( kg/m³ ).
  • Interpreting data from bar charts and recognising scientific limitations/evaluations.
  • States of matter: particle arrangement in gases and how trapped air affects overall density.
Part 01.1 • 1 Mark

Measuring Volume of Irregular Shapes

Why a ruler cannot calculate the rock's volume directly

✅ Correct Answer

Tick box 2:

"The piece of limestone has an irregular shape."

💡 Key Knowledge

A ruler can only be used to find the volume of regular solid objects (cubes, rectangular blocks, cylinders) where geometric formulas like length × width × height can be applied.

❌ Common Errors

Blaming the ruler's accuracy or uncertainty. Rulers are sufficiently accurate for length, but geometry cannot account for lumps and bumps on a rock without displacement.

Award 1 mark for selecting "The piece of limestone has an irregular shape". Any other box ticked = 0 marks.
Part 01.2 • 4 Marks (Level of Response)

Required Practical Method: Displacement Technique

Describe a method to determine the volume of the piece of limestone

✅ Model Answer (Displacement Can Method)

  1. Fill the displacement (Eureka) can with water until the water level reaches just below the spout (or allow excess to drip out).
  2. Place an empty measuring cylinder underneath the spout.
  3. Carefully lower the limestone into the water so it is completely submerged, taking care to avoid splashing.
  4. Collect the displaced water in the measuring cylinder.
  5. Read the volume of displaced water in the measuring cylinder; this equals the volume of the limestone.

🧠 Level 2 Marking Criteria (3–4 marks)

To reach Level 2 (3–4 marks), your method must:

  • Explicitly mention submerging the rock completely.
  • State using the measuring cylinder to measure the displaced volume.
  • Be logically ordered so another student could follow it to obtain a valid result.

💡 Alternative Method: Large Measuring Cylinder

  • Part-fill a large measuring cylinder with water and record the initial volume ( V₁ ).
  • Submerge the limestone completely.
  • Record the new final volume ( V₂ ).
  • Calculate volume: Volume = V₂ - V₁ .

❌ Common Student Mistakes

  • Saying "collect water in a beaker" and stopping there — a beaker lacks precision markings; you must measure using a measuring cylinder.
  • Forgetting to state that the stone must be fully submerged.
  • Dropping the stone roughly and causing splashes (loses water and gives an inaccurate volume).
Level 2 (3–4 marks): A coherent method leading to a valid outcome. Level 1 (1–2 marks): Steps identified but with gaps or lack of logical sequence.
Part 01.3 • 2 Marks

Calculating Density

Mass = 155 g, Volume = 62 cm³

📐 Step-by-Step Calculation

  1. Identify formula:
    density = mass ÷ volume
  2. Substitute values:
    density = 155 ÷ 62 [1 mark]
  3. Calculate final value:
    density = 2.5 g/cm³ [1 mark]

🧠 Exam Tip

Always show your substitution clearly! Even if you press the wrong button on your calculator, you will still earn 1 mark for writing 155 / 62 .

❌ Common Errors

Inverting the fraction (e.g. calculating 62 ÷ 155 = 0.4 ). Remember: density is "mass divided by volume", not volume divided by mass.

1 mark for correct substitution (155 / 62); 1 mark for correct answer (2.5).
Part 01.4 • 1 Mark

Alternative Units of Density

Identifying standard SI units

✅ Correct Answer

Tick box 2:

kg/m³ (kilograms per cubic metre)

💡 Units Breakdown

  • Mass is measured in kg (or g).
  • Volume is measured in m³ (or cm³).
  • Therefore, unit of density = mass unit / volume unit = kg/m³.

❌ Distractors to Avoid

Watch powers and divisions: kg³/m or kg³/cm have cubes on the wrong unit!

Award 1 mark for ticking kg/m³.
Parts 01.5, 01.6 & 01.7 • 3 Marks Total

Data Analysis & Chart Interpretation

01.5 Bar Chart Drawing (1 mark)

Action: Draw a straight bar for the "Unknown rock" up to exactly 2.4 g/cm³.

Check the vertical scale: 1 large grid square (10 small divisions) = 0.5 units, so each small square is 0.05. The line must sit precisely 8 small squares above 2.0.

01.6 Identifying the Rock (1 mark)

Answer: obsidian

Reason: Looking at Figure 3, obsidian has a bar height of exactly 2.4 g/cm³, matching the unknown rock.

01.7 Why We Cannot Be Certain (1 mark)

Answer:

  • "Other types of rock may have the same density as obsidian." OR
  • "Not all types of rock in the world are plotted on the chart."

❌ Common Mistake in 01.7

Saying "the experiment had errors" or "the student measured incorrectly". The question asks why you cannot be certain even if the data is accurate: density alone is not completely unique to a single type of rock.

01.5: 1 mark for bar drawn accurately to 2.4 g/cm³. | 01.6: 1 mark for 'obsidian'. | 01.7: 1 mark for recognizing other rocks could share that density.
Parts 01.8 & 01.9 • 2 Marks Total

States of Matter: Air Inside Pumice

01.8 Particles in Air (1 mark)

Tick the 4th box (diagram showing widely spaced, randomly arranged particles).

Diagram features:

  • Particles are far apart with lots of empty space.
  • No regular pattern or touching rows.

01.9 Effect of Air on Density (1 mark)

The holes containing air cause the density of pumice to be less than the density of other types of rock.

💡 Physical Explanation

Gases have very low densities because the particles are very far apart compared to solids. Pumice contains trapped pockets of air, giving it a large volume for its mass. This lowers its average density (so low it often floats in water!).

❌ Visual Particle Trap

Box 1 shows a regular grid (crystalline solid), Box 2 shows close-packed solid, Box 3 shows a liquid (particles touching but disordered). Only Box 4 represents a gas.

01.8: 1 mark for the 4th box. | 01.9: 1 mark for 'less than'.

Topics

Physics · P3: Particle Model of Matter

Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Physics Paper 1 (Foundation), November 2021. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.