����ý

There are different ways to investigate methods of insulation. In this practical activity, it is important to:

• make and record measurments of temperature and time accurately
• measure and observe the effect of the different thicknesses of the insulator
• use appropriate apparatus and methods to measure the effectiveness of different thicknesses of thermal insulators

Aim of the experiment

To compare the effectiveness of different thicknesses of thermal insulators.

Method

1. Wrap a sheet of newspaper around a 100 ml beaker.
2. Fill the beaker with hot water from a kettle.
3. Put a piece of cardboard over the beaker as a lid. The lid should have a hole suitable for a thermometer.
4. Place a thermometer into the beaker through the hole.
5. Record the temperature of the water in the beaker and start the stopwatch.
6. Record the temperature of the water every 2 minutes for 20 minutes.
7. Repeat steps 1-6, each time adding another layer of newspaper around the beaker until there are 10 layers of newspaper wrapped around the beaker.
8. Plot graphs of temperature against time.

Results

Analysis

For each layer, plot a line graph of temperature on the y-axis and time on the x-axis. Plot all of the curves on the same axes. This will make the different thicknesses easier to compare.

Evaluation

This graph shows:

• The curve which takes the longest time for the water temperature to drop (the shallowest gradient) shows the amount of layers that provide the best insulation.
• The curve for no insulation has the steepest gradient at any given time interval when compared to any other curve. As the number of layers increases, the gradient of each curve decreases at any given time interval.
• Having more layers of paper increases the insulation which means the temperature drops more slowly. The thickest insulation has the lowest rate of cooling.
• The temperature falls quickly at high temperatures and slowly at low temperatures.

Hazards and control measures