Required Practical: Investigating Insulation

Aim

investigate the effectiveness of different materials as thermal insulators

Independent variable

time

dependent variable

temperature

control variable

• volume of water

• initial temperature of water

• thickness of each material

Method

1. Place a small beaker inside a larger beaker

2. fill the small beaker with boiling water from a kettle

3. place a piece of cardboard over the beaker as a lid. It should have a hole for a thermometer and place the thermometer through this hole and into the water in the small beaker

4. Record the temperature of the water in the small beaker and start the stopwatch

5. Record the temperature of the water every 2 minutes for 20 minutes, or until the water reaches room temperature

6. Repeat the experiment with water of the same amount and temperature, each time changing the cardboard for another insulating material and also without any insulation as a control

Analyse the graph

temperature falls quickly at high temperatures, then more slowly, shown by the graph levelling out

• at higher temperature there is a greater temperature difference between it and room temperature so greater energy transfer by heating

The shallowest curve shows longest time for temperature to drop

• best insulator

Systematic errors

1. Cover around the beaker with insulator to reduce heat transfer by conduction through the glass

2. Use a data logger connected to a thermometer for more accurate results

Random errors

1. Hole not too big to prevent E transfer

2. Repeat readings- accurate

3. Read thermometer at eye level to prevent parallax error