IGCSE Physics Required Practicals Summary

This page lists the key practicals in the IGCSE Physics 0625 syllabus. For each practical, we cover the method, what to measure and common exam questions.

Topic 1: Motion, Forces and Energy

Measuring speed using a trolley and ramp

Method: Release a trolley from the top of a ramp. Use a stopwatch (or light gates) to measure the time to travel a known distance. Key measurements: Distance (metre rule), time (stopwatch or light gate timer). Calculation: speed = distance / time. Common exam questions: Describe how to reduce timing errors (use light gates, or time multiple runs and average). Explain why the trolley accelerates (component of weight along the ramp).

Hooke’s Law experiment

Method: Hang masses from a spring. Measure the extension for each mass. Key measurements: Original length of spring, length with each mass (ruler), mass added (known masses). Calculation: Plot force (y-axis) against extension (x-axis). Gradient = spring constant. Common exam questions: Identify the limit of proportionality on the graph. Explain what happens beyond the elastic limit.

Measuring density

Method: Measure mass (balance) and volume (ruler for regular shapes, displacement can for irregular shapes). Calculate density = mass / volume. Common exam questions: Describe the displacement method for an irregular solid. Explain sources of error (water clinging to the object, reading the meniscus incorrectly).

Principle of moments

Method: Balance a metre rule on a pivot. Place known masses at measured distances from the pivot. Adjust until the rule balances. Verification: Check that the sum of clockwise moments equals the sum of anticlockwise moments.

Topic 2: Thermal Physics

Measuring specific heat capacity

Method: Use an electrical heater to heat a known mass of material. Measure the temperature rise and the energy supplied (E = P x t or E = V x I x t). Calculation: c = E / (m x change in T). Common exam questions: Explain why the measured value differs from the accepted value (energy lost to surroundings). Suggest improvements (insulation, stirring for liquids).

Heating and cooling curves

Method: Heat a substance and record temperature at regular time intervals. Plot temperature against time. Key observations: Flat sections of the graph indicate a change of state (melting or boiling). Temperature remains constant during the change.

Comparing rates of cooling

Method: Fill identical containers with hot water. Wrap each in a different material. Record temperature at regular intervals. Common exam questions: What variables must be controlled? (Same volume, same starting temperature, same container.) Which material is the best insulator? (Smallest temperature drop.)

Topic 3: Waves

Reflection of light

Method: Shine a ray of light at a plane mirror. Measure the angle of incidence and angle of reflection using a protractor and the normal line. Key result: Angle of incidence = angle of reflection.

Refraction of light through a glass block

Method: Shine a ray through a rectangular glass block. Mark the incident ray, refracted ray and emergent ray. Measure angles of incidence and refraction. Common exam questions: The ray bends toward the normal when entering a denser medium. Calculate the refractive index.

Measuring the speed of sound

Method: Clap or bang at a known distance from a large wall. Time the echo. Distance = 2 x distance to wall. Speed = distance / time. Alternative method: Use a microphone and data logger to measure the time interval between a sound and its echo.

Topic 4: Electricity and Magnetism

V-I characteristics

Method: Set up a circuit with a variable power supply, ammeter and voltmeter. Vary the voltage and record the current for a resistor, filament lamp and diode. Key results: Resistor gives a straight line through the origin. Filament lamp curves upward. Diode conducts in one direction only.

Resistance of a wire

Method: Measure voltage across a wire and current through it for different lengths. Calculate R = V / I for each length. Common exam questions: What is the independent variable? (Length.) What must be controlled? (Thickness, material, temperature.)

Magnetic field patterns

Method: Place a magnet under a sheet of paper. Sprinkle iron filings on the paper and tap gently. The filings align with the field lines. Alternative: Use a plotting compass to trace field lines.

Topic 5: Nuclear Physics

Measuring background radiation

Method: Use a Geiger-Muller (GM) tube and counter. Record counts for several minutes with no source present. Calculate the average background count rate. Common exam questions: Why must you subtract the background count from the reading with a source? Why do you count for several minutes? (To reduce the effect of random variations.)

General practical skills tested

Planning

• Identify independent, dependent and control variables.
• Select appropriate equipment.
• Write a clear method.

Recording

• Record data in a properly headed table with units.
• Use appropriate precision for the measuring instrument.

Analysing

• Plot data on a graph with correctly labelled axes.
• Draw a line of best fit.
• Calculate gradients and read intercepts.

Evaluating

• Identify sources of error.
• Suggest improvements.
• Assess the reliability of results.