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Integrated Science Recap – Introducing Science | Jack (2026)

Introducing Science

Jack (2026)

Monday, 31 August 2026

01

Experiment Details

Variables and Fair Testing

A student investigates how the temperature of water affects the time taken for a vitamin tablet to completely dissolve. The student uses 100 cm³ of water and one identical vitamin tablet for each test. The mixture is not stirred.

  1. Identify the independent variable in this investigation.
  2. Identify the dependent variable in this investigation.
  3. Identify two controlled variables mentioned in the scenario.
  4. Explain why it is important to keep the volume of water the same to ensure a fair test.
  5. Write a suitable hypothesis for this investigation.
6 marks
02

Data Analysis

Repeated Readings and Anomalies

A student measures the time taken for a toy car to travel down a ramp. The student repeats the test five times under the exact same conditions. The results are recorded in the table below.

Trial 1 2 3 4 5
Time / s 3.12 3.15 3.11 4.50 3.14
  1. Identify the anomalous result in the table.
  2. Explain why this result is considered anomalous.
  3. Suggest one possible cause for this anomalous result (a random error).
  4. Calculate the mean time, excluding the anomalous result. Show your working.
  5. Explain why excluding the anomalous result before calculating the mean makes the final conclusion more reliable.
6 marks
03

Measurement

Precision, Accuracy, and Reliability

Two students measure the length of the same leaf. Student A uses a ruler marked only in centimetres and records: 6 cm, 6 cm, 6 cm. Student B uses a ruler marked in millimetres and records: 6.2 cm, 6.4 cm, 6.3 cm.

  1. Which student’s apparatus is more precise? Explain your answer.
  2. Calculate the mean length from Student B’s readings.
  3. A third student records the mean length as 6.30000 cm. Explain why this is not an appropriate way to record the result.
  4. Explain the difference between a reliable result and an accurate result.
6 marks

Question 1

  1. Temperature of water.
  2. Time taken for the vitamin tablet to dissolve.
  3. Volume of water (100 cm³) and the type/size of the vitamin tablet (also acceptable: no stirring).
  4. The volume of water can affect how quickly the tablet dissolves. If the volume changes, we cannot be sure if the change in dissolving time is due to the temperature or the volume of water.
  5. If the temperature of the water is higher, then the vitamin tablet will dissolve faster. (Must show a relationship between the independent and dependent variables).

Question 2

  1. 4.50 s (Trial 4).
  2. It does not fit the pattern of the other results. It is much higher than the other readings which are all close to 3.13 s.
  3. The stopwatch was started or stopped at the wrong time, or the car hit the side of the ramp (any sensible random error).
  4. Mean = (3.12 + 3.15 + 3.11 + 3.14) / 4 = 12.52 / 4
    Mean time = 3.13 s.
  5. Removing it gives a mean that better represents the consistent repeated readings, reducing the effect of random errors on the final conclusion.

Question 3

  1. Student B’s ruler is more precise. It has smaller divisions (millimetres), allowing for more precise measurements than a ruler marked only in centimetres.
  2. Mean = (6.2 + 6.4 + 6.3) / 3 = 18.9 / 3
    Mean length = 6.3 cm.
  3. The number has too many decimal places for the measuring instrument used. It gives a false impression of precision that the ruler cannot provide.
  4. Reliable results are consistent (repeatable) when the experiment is done again under the same conditions. Accurate results are close to the true value. Reliable results can still be inaccurate if there is a systematic error (e.g., a poorly calibrated ruler).
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