Investigating what kinds of materials are best at keeping water in a boiling tube warm.

Insulators

Introduction

This practical investigation involves investigating what kinds of materials are best at keeping water in a boiling tube warm. A material that prevents this heat loss is called an insulator. Insulators have to prevent three types of heat loss:
· Conduction
· Convection
· Radiation

Conduction of heat occurs mainly in solids. This process is where vibrating particles pass their extra vibration energy to neighbouring particles.

Convection of heat only occurs in liquids and gasses. Convection occurs when the more energetic particles move from the hotter region to the cooler region taking their energy with them.

Radiation of heat can also be called infer-red radiation. Heat radiation can travel through a vacuum. This process is different from the other two it travels in straight lines and at the speed of light. This is the only way heat can reach us from the sun. Heat radiation travels through transparent media like air, glass, and water. No particles are involved in this process it is the transfer of heat energy purely by waves.

In this investigation I will be looking at conduction of heat through the boiling tube.

Aim
I aim to investigate what type of material is the best insulator. Out of the materials I will conduct the experiment, I want to conclude which is best and what factors effect its efficiency.

Prediction
I predict that these factors will effect the efficiency of the material.
· Colour
· Thickness
· Density

The lighter the material in colour the better insulator it will be. I predict this because light colours are poor radiators, therefore they will reflect the heat back into the boiling tube.

The darker materials will absorb the heat and release it the other side so is a bad insulator.

The thickness and density of the material will also have a significant impact on the materials efficiency. Air is a very poor conductor, so materials with lots of large air pockets will be good insulators. For the material to have lots of air pockets it has to be less dense and quite thick. The air trapped in the pockets will prevent convection currents and trap warm air. These factors will help to reduce heat loss. A poor insulator will be thin with small if any air pockets, allowing heat convection and conduction increasing heat loss rapidly.

Based on the above evidence I predict the following for the different materials.
Blue Knitted Acrylic- I think this will be a sufficient insulator because although the material is of a dark colour it is quite thick and is knitted so will contain lots of air pockets.
Pink Knitted Cotton - I don´t think this will be a good insulator as the material is quite dark absorbing the heat. The material is also very thin, containing little air pockets.
Cream Woven Wool - I think this will be one of the best insulators because it is of a light colour reflecting the heat back into the boiling tube. The material is also woven providing large amount of air pockets.
White Pleated Cotton - I don´t think this will be a good insulator because it is very thin. The material is pleated so has very little air pockets. The material is of a light colour so however will reflect a certain amount of heat back onto the water.

Method
For this investigation I will need the following apparatus:

· Boiling tubes
· Thermometers
· Leather
· Kettle- to heat water
· Elastic bands
· Beaker

· Materials being tested:
-Blue knitted acrylic
-Pink knitted cotton
-Cream leather
-White pleated cotton

This is a preview of the whole essay

Method
For this investigation I will need the following apparatus:

· Boiling tubes
· Thermometers
· Leather
· Kettle- to heat water
· Elastic bands
· Beaker

· Materials being tested:
-Blue knitted acrylic
-Pink knitted cotton
-Cream leather
-White pleated cotton

I will set up the apparatus as shown in the diagram below:
I will boil some water using the kettle. I will then pour the hot water into a beaker and then into the boiling tube. The boiling tube will be rapped in one of the selected materials, supported by elastic bands. I shall put leather and the thermometer at the top of the boiling tube. The leather will secure the thermometer and seal the boiling tube. I will record the temperature of the water over a 6oo second period. I will take the temperature every 30 seconds. I will repeat this for each material three times allowing me to achieve ad accurate result.

I will repeat this for each of the above materials recording my results in a table as I conduct my investigation.

Once I have completed this method for all the materials, I will then conduct the method using no material. This will enable me to watch and observe the effect of any type of insulation.
Fair Testing
Throughout conducting my investigation I will take a number of precautions to ensure my experiments fair.
· The water starts at the same temperature.
This will enable me to assess the cooling rate accurately.

· The same amount of water is used.
Different amounts of water will largely affect the cooling rate making the experiment inaccurate.

· The same amount of material is used.
Although the materials might be different in thickness etc. it is important that they cover the same area.

· I will repeat each experiment three times.
This allows me to achieve an accurate and fair result.

Safety
I will also take a number of safety precautions whilst conducting the investigation. I will ensure the kettle is used safely through out the experiment, and hot water is transferred securely. I will conduct the experiment using leather in place of corks, as this reduces the risk of the thermometers breaking. I will use protection when handling the boiling tubes when the hot water is present.
Results

I recorded all my results in a table as I conducted the experiments.
These are my results:

Blue Knitted Acrylic
Time in seconds Temperature In ºC
1 2 3 Average
0 65 65 65 65
30 63 63 65 64
60 62 63 65 63.5
90 61 62.5 64 62.5
120 61 62.5 64 62.5
150 60 62 63 62
180 59 61.5 62.5 61
210 59 61 61.5 60.5
240 58.5 60 61 60
270 58 60 60 60
300 57.5 59.5 59.5 59
330 57 59 59 58.5
360 57 58 58 57.5
390 56 57.5 58 57
420 55.5 57 56 56
450 55 56.5 56 56
480 54.5 56 56 55.5
510 54 55.5 56 55
540 54 55 55 54.5
570 53.5 54.5 54.5 54
600 53 54 54 53.5

Pink Knitted Wool
Time in seconds Temperature In ºC
1 2 3 Average
0 65 65 65 65
30 64 64 64 64
60 63 63.5 63 63
90 62 61 62 61.5
120 61 60 61.5 61
150 60 60 61 60.5
180 59 59.5 60.5 60
210 58 59.5 59.5 59.5
240 58 58 59 58.5
270 57 57 58.5 57.5
300 56.5 56 58 57
330 56 56 57 56.5
360 55 55 56 55.5
390 54 54 54 54
420 53 54 53 53.5
450 53 53 51.5 52.5
480 52.5 52.5 51 52
510 51 52 51 51.5
540 51 52 50.5 51
570 50 52 50.5 51
600 49.5 51 49 50

Cream Woven Wool
Time in seconds Temperature In ºC
1 2 3 Average
0 65 65 65 65
30 63 65 64 64
60 62 64 63 63
90 61 64 62 62
120 61 63 61 62
150 60 62 60 61
180 58 62 59 60
210 57 61 59 59
240 55 59 58 57
270 55 59 57.5 57
300 54 58 57 56
330 53 58 56.5 56
360 52 58 56 55.5
390 52 57 55.5 55
420 52 56 54.5 54.5
450 52 55.5 54 54
480 51.5 55 54 54
510 51 55 53 53
540 50 54 53 53
570 50 54 52 52
600 49 54 52 52

White Pleated Wool
Time in seconds Temperature In ºC
1 2 3 Average
0 65 65 65 65
30 64 64 63 64
60 62 63 62 63
90 60 62 62 61
120 60 61.5 61 61
150 59 60.5 60 60
180 58 60 59 59
210 57 59 59 58
240 57 58.5 58 58
270 56 58 57 57
300 55.5 57 56 56
330 55 56.5 5535 56
360 54.5 55.5 55 55
390 54 54 54 54
420 54 54 54 54
450 53 53 53 53
480 53 53 53 53
510 52 52 52 52
540 51 52 51.5 51.5
570 50 51 51 51
600 50 50.5 50 50

No Insulation
Time in seconds Temperature In ºC
1 2 3 Average
0 65 65 65 65
30 64 63 64 64
60 63 63 63 63
90 61.5 62 61 61.5
120 61 60 60 60
150 60 58 58 59
180 59 58 57.5 58
210 58 57 56.5 57
240 57 56 55 56
270 56 55 54 55
300 56 54 53 54
330 55 53 52.5 53.5
360 54 53 52 53
390 53 52 51 52
420 52 51 55 51
450 51 50 49.5 50
480 50 50 49 50
510 49 49 48 49
540 49 48 47.5 48
570 48 47 47 47
600 47 46 46 46
The table below shows all the temperature averages for the different materials.

Temperature Averages
Time in Seconds Temperature in ºC
Blue knitted Acrylic Pink Knitted Wool Cream Woven Wool White Pleated Cotton No Insulation
0 65 65 65 65 65
30 64 64 64 64 64
60 63.5 63 63 63 63
90 62.5 61.5 62 61 61.5
120 62.5 61 62 61 60
150 62 60.5 61 60 59
180 61 60 60 59 58
210 60.5 59.5 59 58 57
240 60 58.5 57 58 56
270 60 57.5 57 57 55
300 59 57 56 56 54
330 58.5 56.5 56 56 53.5
360 57.5 55.5 55.5 55 53
390 57 54 55 54 52
420 56 53.5 54.5 54 51
450 56 52.5 54 53 50
480 55.5 52 54 53 50
510 55 51.5 53 52 49
540 54.5 51 53 51.5 48
570 54 51 52 51 47
600 53.5 50 52 50 46

I presented these results on a line graph. (Next page)

The graph shows the rate the water temperature decreases when insulated by the different materials. The results are very close together but they clearly show that the blue knitted acrylic is a successful insulator. It also shows obviously that the test tube with no insulation decreased fastest. I also shows that the white pleated cotton and the pink woven wools temperature also decreased rapidly.
The table below shows the difference between the start temperature and the end temperature for each material. It also shows the average heat loss per second.

Material Start TemperatureºC End TemperatureºC Average heat loss per second ºC
Blue Knitted Acrylic 65 53.5 0.019
Pink Woven Wool 65 50 0.025
Cream Woven Wool 65 52 0.022
White Pleated Cotton 65 50 0.025
No Insulation 65 46 0.032

By looking at the table it is clear that the water with no insulation decreased in temperature more rapidly than the boiling tubes with material insulation. I expected this. The other materials decrease in temperature in the following order:
1. White pleated cotton / Pink woven wool (temperature decreased fastest)
2. Cream woven wool
3. Blue Knitted cotton. (most efficient insulator)

Analysing my Results and Observations
My results state clearly that the best insulator material was the Blue Knitted Cotton. This does not match my prediction entirely because I predicted that a light coloured material would be the best insulator. However it does match my prediction because the Blue Knitted Cotton has the most air pockets. This means that the primary factor in preventing heat loss is stopping convection currents and trapping warm air. The reduction of convection currents must have been grater then the radiation to make this material the most efficient insulator.

The two most inefficient insulators were the White pleated cotton and the Pink woven wool. This surprised me because I thought that the white pleated cotton would be an efficient insulator. The White pleated cotton has little air pockets because it is pleated. This method reduces the amount of air pockets in the fabric. The pink woven wool I predicted would be a poor insulator because it is a dark colour. It also has little are pockets as it is woven. Therefore this result matched my prediction.

The Cream woven wool is a fairly good insulator. The fabric is woven so has a restricted amount of air pockets, but is of a light colour so reflected heat back into the boiling tube.
This resulted collaborated with my prediction

Evaluating my results
My results clearly showed how the two factors I predicted effected the materials efficiency. It also showed to what extent the factors effected the efficiency of the insulator. I concluded that the best insulator was the Blues Knitted Acrylic material, and also put the other materials in order of efficiency. I think my results achieved my aim and matched my prediction.

Evaluating the Investigation
The investigation was fair and the experiments I conducted achieved the required results. The experiments were accurate and produced correct answers with no anomalous results. If I conducted the experiment again I would use a wider variety of materials with a wider range of colours. I would want to do this because then I could investigate further into how the colour of the material effects my results. I would use the same material but in different colours for each test. I would also use the same colour material but in different textures e.g. woven pleated, platted, knitted etc. This would enable a more accurate evaluation of results.

The method I chose to use was successful and worked well within the investigation, it was stable and fair. I would not change the method if I repeated the investigation.

Overall I think my investigation was successful as it achieved the required results fairly and accurately, answering the set hypothesis.