Edexcel A-Level Physics Repeat Readings

Practise Edexcel A-Level Physics repeat readings by deciding when repeats are useful, reducing random error and calculating mean values.

Exam points

use repeat readings and mean values to reduce the effect of random measurement errors
decide when repeats are not useful because readings show little random variation
improve flow-rate timing by fixed markers, fixed volumes, repeats or electronic timing

[Maximum number: 2]

A student is investigating the effect of temperature on the viscosity of oil by measuring how fast the oil flows through a funnel. He uses the apparatus shown.

Figure for Question 3.3.6 - Repeat readings question 1 — Edexcel A-Level Physics AS

The student initially measures the time from starting to pour the oil into the funnel to the last drop of oil falling from the funnel.

Describe how the same apparatus could be used to calculate a more accurate value for the rate of flow of the oil.

Max 2 from

- Starting timer after oil has been poured e.g. marking a start position, starting at $10 \mathrm{~cm}^{3}$

(1)

- Stopping timer before the funnel is empty e.g. stopping after a fixed volume or at a marker

(1)

- Record the volume after a fixed time period (1)

- Repeat for the same temperature and calculate the mean time (1)

- Use of light gates and (electronic) timer to avoid (human) reaction time

(1)

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3.3.6 - Repeat readings question 1