Physics experiments and data questions

Learning outcomes that say investigate, determine or verify are practical work, and the written paper can ask about them. The skills are the same each time: variables, a fair test, processing results and a justified conclusion.

Variables	Independent, dependent and controlled
Results	Graphs, slopes, intercepts, means and uncertainties
Quality	Repeatability, reproducibility, accuracy and error
Our practice	An experiment and data question in every section

Name the variables first

Say what was changed, what was measured and what was kept the same, then say how it was kept the same. A control lets you see the effect of the variable you changed.

Use the numbers

When a question gives data, quote it: the value, the trend and any anomaly. Plot the right pair of quantities so the graph is a straight line, and use its slope, with units.

Conclude only what the data shows

A conclusion answers the question the experiment asked and stays within the range tested. Suggest an improvement that would make the results more repeatable or more valid.

Try 2 questions

Question 1 · Both levels

The graph shows the force applied to a spring against its extension. It is a straight line through the origin up to an extension of 4.0 cm and then curves. What is the spring constant of the spring within its limit of proportionality?

Question 2 · Both levels

Resistance of four resistors at five temperatures.
Temperature / °C	P / Ω	Q / Ω	R / Ω	S / Ω
0	100	800	50	200
25	110	420	51	205
50	120	230	52	215
75	130	140	53	235
100	140	90	54	270

A student tests four resistors, P, Q, R and S, as possible thermometers for 0 °C to 100 °C. She wants a reading that changes by the same amount for every degree, so the scale can be marked evenly, and that changes by as much as possible for each degree. The table gives each resistance at five temperatures. Which resistor should she choose?

Next step

Take the free test Start the heat lesson

Questions people ask

Are there still mandatory experiments?

The new specification sets learning outcomes, some of which say investigate, verify or determine using primary data. Your teacher plans the practical work that meets them.

Do I need to learn exact methods?

Know why each step is done. Questions often change the details, so understanding beats memorising.

Temperature / °C	P / Ω	Q / Ω	R / Ω	S / Ω
0	100	800	50	200
25	110	420	51	205
50	120	230	52	215
75	130	140	53	235
100	140	90	54	270

Temperature / °C	P / Ω	Q / Ω	R / Ω	S / Ω
0	100	800	50	200
25	110	420	51	205
50	120	230	52	215
75	130	140	53	235
100	140	90	54	270

Temperature / °C	P / Ω	Q / Ω	R / Ω	S / Ω
0	100	800	50	200
25	110	420	51	205
50	120	230	52	215
75	130	140	53	235
100	140	90	54	270