- Aluminium is a shiny bright material therefore it will allow more heat to escape.
- Felt is a dark, matt material thus allowing more heat to be contained. Also, due to the weave of the material it can trap a greater amount of air, allowing more insulation.
- Polystyrene is a bright, matt material which may allow some heat loss; however, due to air that is trapped within it, the air will become part of the insulator.
- Copper is a dark matt surface which won’t reflect, however, heat may still be lost
- Most heat will be lost through radiation.
Apparatus:
- Thermometer
- Fake Fur
- Copper cylinder
- Aluminium
- Felt
- Polystyrene
- Kettle – boiling water
- Stopwatch
Safety:
- Wear goggles at all times
- Keep a bench mat beneath the equipment
Fair test: To ensure this experiment was conducted fairly, we will note down the results every 30 seconds for 300 seconds altogether. We will do this for each material and experiment. Additionally, we will take 2 readings of the each experiment and calculated an average for more accurate results.
Variables: Controlled – The amount of hot water will be kept the same at 230ml per test. We will be recording each result every 30 seconds for a total of 300 sec/600 seconds.
Independent – We will use different materials
Dependent – We are measuring the amount of heat loss, which will depend on the insulation.
Results:
The following result table shows the temperature of the water with each material recorded every 30 seconds.
Average table of results (to 1 decimal places). This table also displays the change in temperature, which is the final temperature subtracted from the initial or first temperature.
We also combined the two good insulators to reduce the amount of heat energy loss:
Energy loss:
We can calculate the heat energy loss through each material by conduction:
Heat lost (joules)= u x surface area x temperature difference x time
To calculate the area of the insulating material,
Total Surface area = 2π rh + π r2
= 2π x 0.09 x 0.10 + π (0.09)2
= 0.034m2
The ‘u’ value is the heat energy lost per second through each m2 of the material, when the temperature difference between the surfaces is 10C.
For example,
Copper = 401,000 x 0.034m2 x 7.30C x 300/600
= 29858460 or 59716920
Aluminium = 35294040
Felt = 146.88
Polystyrene = 33.66
There is no ‘u’ value for fur.
Graphs:
Figure 1 - graph showing how different insulators affect the temperature of hot water
Figure 2 - graph showing combination of polystyrene and felt
Figure 3 - bar graph showing change in temperature for each material
Figure 4 – graph showing heat loss
Conclusion:
In conclusion, the experiment proved that my hypothesis was correct. Polystyrene was the best insulator, and felt was second best.
Evaluation:
The experiment was fairly accurate; we did have one anomalous result in table 1.
This could be due to a misreading of the thermometer or it was not placed inside the water correctly.
The experiment could be improved by using different materials to extend the investigation and finding a more practical way of combining two or more materials together.
