GCSE Physics Practical Overview

Overview

This lecture reviews the required practicals for AQA GCSE Physics Paper 2, including their methods, variables, safety, accuracy, and exam tips.

Set up a spring and meter ruler parallel using clamp stands.
Measure initial length of the spring at eye level.
Add weights in consistent increments (e.g., 2N) and measure new length each time.
Calculate extension as new length minus initial length; repeat for a range of forces.
Plot force (x-axis) versus extension (y-axis); expect a straight line through the origin (direct proportion).
Control variables: eye-level measurement, ruler-spring alignment.
Independent variable: force applied; Dependent variable: extension.
Safety: wear goggles, keep stand centered.

Set up a car on a slope with a pulley and mass hanger to vary force.
Release the car from a set point, use light gates to measure velocity at two points.
Measure time with a stopwatch; calculate acceleration (change in velocity/time).
Vary force by adding masses to the hanger, keeping total mass constant.
Alternatively, vary cart mass to see effect on acceleration (inverse proportionality).
Control variables: slope angle and distance between light gates.
Safety: catch the car at the end of the slope.

Use a ripple tank with a lamp above and a straight-edged motor to create waves.
Measure frequency by counting waves passing a point in 10 seconds, then divide by 10.
Measure wavelength by measuring distance across 10 waves, then divide by 10.
Calculate wave speed with wave speed = frequency × wavelength.
Accuracy: use large sample (10 waves/seconds), consider taking photos or videos.

Set up a vibration generator attached to a string; count loops (wavelengths).
Frequency is set by the generator.
Measure wavelength across multiple loops with a meter ruler, divide total length by number of wavelengths.
Calculate wave speed (frequency × wavelength).
Accuracy: avoid parallax errors by reading ruler at eye level.

Fill Leslie cube or containers with hot water; surfaces differ (e.g., matte black, shiny).
Measure heat emitted using a thermometer or radiation detector over set time.
The surface with the biggest temperature drop is the best emitter (usually matte black).
For absorption, use equal volumes of cold water, expose to heat source, and measure temperature increase.
Control variables: water volume, initial temperature, detector distance.
Independent variable: surface type; Dependent variable: temperature/radiation.

For reflection: use a mirror, draw the normal, and shine light at known angles; measure angle of incidence and reflection.
For refraction: use a glass block, mark incident and refracted rays, measure angles.
Expect i = r for reflection; i > r for refraction.
Repeat with different angles; plot graphs as required.
Inaccuracy source: wide beam width from ray box makes angle measurement difficult.
Safety: ray box becomes hot, allow to cool before handling.

Independent variable — the factor you change in an experiment.
Dependent variable — the factor you measure in an experiment.
Control variable — factors kept the same to maintain a fair test.
Directly proportional — both variables increase at the same rate.
Inversely proportional — as one variable increases, the other decreases.
Parallax error — mistake from not viewing a measurement at eye level.
Angle of incidence (i) — angle between the incoming ray and normal.
Angle of reflection/refraction (r) — angle between reflected/refracted ray and normal.

Revise the methods, variables, and safety/accuracy points for each required practical.
Practice drawing and interpreting graphs from practical data.
Memorize the formulae and definitions listed in Key Terms.
If separate science, review reflection and refraction practicals as well.