Density of Irregular Solids - Test

AQA GCSE Physics Density of Irregular Solids required practical. ‍Combined & Triple Science.

Need to revise first? Study the illustrated Density practical.

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A student wants to determine the density of the irregularly shaped stone, shown in Figure 1.

Plan a valid method to determine its density in kg/m³.

[6 marks]

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Measure

• How do we use the equipment to measure Mass?

  • Place the dry stone on a balance and record its mass.

• How do we use the equipment to measure Volume?

  • Fill a Eureka can with water until it is perfectly level with spout opening.

  • Place an empty measuring cylinder beneath the spout.

  • Tie a thin thread around the stone and gently immerse it until it is fully submerged.

  • Water will be pouring out of the spout and into the measuring cylinder

  • Once all the stone is fully immersed and all the water has poured out into the measuring cylinder, read the water level in the measuring cylinder.

  • The displaced water is equal to the volume of the stone.

Calculate

• How do we calculate Density?

  • Convert volume from cm³ to m³

  • Convert mass from g to kg

  • Divide the mass in kilograms by the volume in cubic metres.

  • Density = mass ÷ volume

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Exam Challenge

• Now, answer the original 6-mark question without looking back. Then reveal the answer here.

  • Place the dry stone on a balance and record its mass.

  • Fill a Eureka can with water until it is perfectly level with spout opening.

  • Place an empty measuring cylinder beneath the spout.

  • Tie a thin thread around the stone and gently immerse it until it is fully submerged.

  • Water will be pouring out of the spout and into the measuring cylinder

  • Once all the stone is fully immersed and all the water has poured out into the measuring cylinder, read the water level in the measuring cylinder.

  • The displaced water is equal to the volume of the stone.

  To calculate density:

  • Convert volume from cm³ to m³

  • Convert mass from g to kg

  • Divide the mass in kilograms by the volume in cubic metres.

  • Density = mass ÷ volume

Missed some steps? Return to this practical’s step-by-step visual explanation.

More Exam-style Questions

• A measuring cylinder records volume in cm³. How do we convert this to m³?

  • 100 cm = 1 m

  • 1,000,000 cm³ = 1 m³

  Divide the volume in cm³ by 1,000,000 to obtain volume in m³.

  Then, you can calculate density by dividing mass in kg by volume in m³.

• Which of these strings should we use to lower the stone into the Eureka can? Why? [2 marks]

  The thin string.

  A thick string would displace too much water, which makes the volume measurement an overestimation, as the displaced water would be a combination of the stone’s volume and the string’s volume. An overestimated volume, would lead to an underestimated density value.

  A thin string would cause minimal discrepancy, so should be used instead.

Continue Revising Paper 1

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