Core Practicals Overview — Physics

This lesson covers the key Physics core practicals for Edexcel GCSE Combined Science (1SC0). These practicals frequently appear on Papers 5 and 6 and are worth learning in detail.

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Core Practical 8: Investigating Thermal Insulation

Aim

To investigate the effectiveness of different materials as thermal insulators by measuring how quickly hot water cools when wrapped in different materials.

Method

1. Measure a fixed volume of hot water (e.g. 100 cm³ at approximately 80 °C) and pour it into a beaker.
2. Wrap the beaker in the insulating material being tested (e.g. bubble wrap, felt, foil, cotton wool). Use the same thickness and coverage for each material.
3. Place a thermometer or temperature probe into the water.
4. Record the temperature every minute for a set period (e.g. 10 minutes).
5. Repeat the experiment with a different insulating material.
6. Include a control — a beaker with no insulation.
7. Repeat each test at least three times and calculate mean temperatures.

Variables

Variable type	Variable
Independent variable (IV)	Type of insulating material
Dependent variable (DV)	Temperature of water at each time interval (or temperature drop over a set time)
Control variables	Volume of water, starting temperature, beaker size, thickness of material, room temperature, lid on/off

Key Results and Conclusions

• The beaker with no insulation (control) cools the fastest.
• Better insulators result in a slower temperature drop — the water stays warmer for longer.
• Materials that trap air (e.g. bubble wrap, cotton wool) tend to be better insulators because air is a poor conductor and the trapped air reduces convection.

Graph

Plot temperature (y-axis) against time (x-axis). Each line represents a different material. The flattest line indicates the best insulator.

Exam Tip: If asked to improve this experiment, suggest using a lid to reduce heat loss by evaporation and convection from the top — this is a very common mark-scheme answer.

Safety

• Handle hot water with care — use tongs or heatproof gloves.
• Place beakers on a heatproof mat.
• Ensure thermometers are secure and will not fall.

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Core Practical 9: Investigating Refraction of Light

Aim

To investigate how the angle of incidence affects the angle of refraction as light passes through a rectangular glass or Perspex block.

Method

1. Place a rectangular glass block on a sheet of white paper and draw around it with a pencil.
2. Use a ray box to shine a narrow beam of light at one face of the block at a chosen angle.
3. Mark the incident ray (the point where it enters the block) and the emergent ray (the point where it exits the other side) using crosses or dots.
4. Remove the block and draw the normal (a line perpendicular to the surface at the point of incidence).
5. Draw the incident ray and the refracted ray (joining the entry and exit points through the block).
6. Measure the angle of incidence (between incident ray and normal) and the angle of refraction (between refracted ray and normal inside the block) using a protractor.
7. Repeat for different angles of incidence (e.g. 10°, 20°, 30°, 40°, 50°, 60°).

Variables

Variable type	Variable
Independent variable (IV)	Angle of incidence
Dependent variable (DV)	Angle of refraction
Control variables	Same glass block, same ray box, same side of block

Key Results and Conclusions

• When light enters the glass (denser medium), it slows down and bends towards the normal — the angle of refraction is less than the angle of incidence.
• When light exits the glass (less dense medium), it speeds up and bends away from the normal.
• The emergent ray is parallel to the incident ray but displaced sideways.
• At 0° incidence (along the normal), there is no refraction — the light passes straight through.

Graph

Plot angle of refraction (y-axis) against angle of incidence (x-axis). The result is a curve — the angle of refraction increases as the angle of incidence increases, but the relationship is not linear.

Exam Tip: A very common question asks why the normal is drawn. Answer: angles of incidence and refraction must be measured from the normal, not from the surface.

Safety

• Do not stare directly into the ray box beam.
• Allow the ray box to cool before handling.
• Handle glass blocks carefully to avoid breakage.

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Core Practical 10: Investigating Density

Aim

To determine the density of regular and irregular solid objects and of liquids.

Method — Regular Solid (e.g. a metal block)

1. Measure the mass using a balance (in grams, then convert to kg).
2. Measure the dimensions (length, width, height) using a ruler or Vernier callipers.
3. Calculate the volume: V = l × w × h.
4. Calculate density: ρ = m ÷ V.

Method — Irregular Solid (e.g. a stone)

1. Measure the mass using a balance.
2. Fill a measuring cylinder with a known volume of water. Record the initial volume.
3. Carefully lower the object into the water. Record the new volume.
4. The volume of the object = final volume − initial volume (this is the displacement method).
5. Calculate density: ρ = m ÷ V.

Method — Liquid

1. Place an empty measuring cylinder on a balance and record its mass.
2. Pour a known volume of the liquid into the measuring cylinder. Record the volume (read the bottom of the meniscus).
3. Record the total mass (cylinder + liquid).
4. Mass of liquid = total mass − mass of empty cylinder.
5. Calculate density: ρ = m ÷ V.

Variables

Variable type	Variable
Independent variable (IV)	Different materials or objects
Dependent variable (DV)	Density
Measurements	Mass (balance) and volume (ruler/callipers or displacement)

Key Equation

$\rho = \frac{m}{V}$ρ=Vm​

Where ρ = density (kg/m³ or g/cm³), m = mass, V = volume.

Exam Tip: Pay attention to units. If mass is in grams and volume is in cm³, density will be in g/cm³. If the question asks for kg/m³, you must convert.

Safety

• Handle heavy objects with care.
• Wipe up any water spills immediately.
• Use a displacement can for larger irregular objects (the water overflows into a measuring cylinder).

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Core Practical 11: Investigating Specific Heat Capacity

Aim

To determine the specific heat capacity of a material (e.g. a metal block or water) by measuring how much its temperature rises when energy is supplied electrically.

Method

1. Measure the mass of the metal block (or a known mass of water) using a balance.
2. Insert a heater and a thermometer into the block (or immerse them in the water).
3. Connect the heater to a joulemeter (or an ammeter + voltmeter + stopwatch to calculate energy).
4. Record the initial temperature.
5. Switch on the heater and allow it to run for a set time.
6. Record the final temperature and the energy supplied (from the joulemeter or calculated as E = I × V × t).
7. Calculate specific heat capacity.

Key Equation

$c = \frac{E}{m \times \Delta T}$c=m×ΔTE​

Where c = specific heat capacity (J/kg°C), E = energy supplied (J), m = mass (kg), ΔT = temperature change (°C).

Variables