How To Answer A Level Physics Questions About Practical Experiments

A Level Physics

Answering 6-mark exam questions about EXPERIMENTS.

Try to include most or all of the following points. This looks like a lot of work but most of these can be covered very briefly.

· EQUIPMENT

o Labelled diagram

o List any equipment not shown in diagram

· METHOD

o What measurements do you need to take?

§ The actual physical measurements (i.e. diameter NOT cross-sectional area)

o What equipment will you use to take each measurement?

§ Mention it, even if it’s something as obvious as using a ruler to measure length.

o Range and values

§ E.g. “Load spring with 100g masses in 10 stages up to a maximum of 1kg.”

o Repeats

§ Take 3 repeats and calculate mean if possible.

§ For Hooke’s Law/Young’s Modulus experiments, repeat readings for loading and unloading.

§ For small readings, measure in large multiples to reduce %-uncertainty (e.g. record time taken for 10 or 20 pendulum swings and then divide by 10 or 20 to calculate time period)

o What calculations do you need to do?

§ (e.g. halve diameter to find radius then A =πr² for cross-sectional area)

· RESULTS

o This is nearly always a GRAPHICAL method, not just subbing one set of results into an equation.

o What will you put on each axis?

§ Something you measured (e.g. current) or something you calculated from your measurements (e.g. resistance)

o What do you need to read from the graph?

§ Gradient? (nearly always!)

§ Intercept? (occasionally!)

§ Something else, like checking for a straight line through the origin (indicating proportionality)

o Any further calculations?

§ E.g. Is your gradient the final “answer” or do you need to multiply/divide by a constant to get the value you’re looking for?

· HEALTH & SAFETY

o This doesn’t seem to be on the mark scheme so much these days but if there’s something obvious like wearing eye protection then mention it – can’t hurt!