Required Practical: Investigating Insulation (OCR GCSE Physics A (Gateway Science Suite)): Revision Notes

You need to be familiar with the practical method used to investigate the effectiveness of insulating materials.

1. Hot water is placed in a container with a thermometer
2. Insulating material is wrapped around the container
3. The type of material, or different thicknesses of a particular material can be investigated
4. The temperature is recorded over a period of time.
5. The temperature change for different materials/thicknesses can be compared

Different substances absorb thermal energy at different rates.

The specific heat capacity of a substance is the energy needed to raise the temperature of 1kg of the substance by 1°C

$∆E$= energy transferred (J)

$m$ = mass (kg)

$c$ = specific heat capacity (J/kg°C)

$∆θ$ = temperature change (°C)

(you will be given this equation on an equation sheet in the exam)

Worked Example 0.15 kg of ice cream mixture was cooled from room temperature (20 °C) to 0°C. This required 6000 J of energy. What is the specific heat capacity of this ice cream?

Rearrange: $c = ∆E ÷ (m∆θ)$

c = 6000 ÷ (0.15x20)

c = 2000 J/kg°C

A storage heater uses electricity at night (when it is cheaper) to heat bricks or concrete blocks inside the heater.