Science Investigation: Insulation Essay, Research Paper
Science Investigation: InsulationIntroduction My investigation is to
find out the rate of which heat transfer happens. Heat transfer is a process in
which energy in the form of heat energy is exchanged between materials that are
at a different temperature. Heat is generally transferred by conduction,
convection, radiation and evaporation. All of these processes can all happen
simultaneously but it is likely that one will give the greater heat exchange.
Heat is exchanged through the brick wall by conduction. The surfaces of a
high-speed aircraft are heated up by convection. The earth is heated by heat
that is being radiated from the sun.
These experiments involved the temperature of hot water being recorded at
chosen intervals in a copper can.
Here is a description of the following processes that will affect my
experiment:
Conduction
This is where heat energy passes through the walls of the can by making the
particles of the can vibrate and then they will make the particles next to them
vibrate causing the heat to pass through the walls of the can and out to the
surroundings. Materials that are good thermal conductors tend to be good
electrical conductors; metals such as gold, silver and copper have high thermal
conductivity’s and will conduct heat readily. Materials such as glass have much
smaller heat transfer values and are poor heat conductors.
Convection
This is where the cooler water particles sink down to the bottom and the warmer
water particles float up to the top. Convection will only affect my experiment
if I did not have a lid. This is because the warm water will float up to the
top and the heat energy will escape out of the top. If a pan of water was being
heated from below then the water particles at the bottom of the pan will become
warm as therefore become less dense, they will begin to rise to the top of the
pan. As the warmer water particles begin to rise, the cooler water particles at
the top of the pan will sink to the bottom, as they are less dense. Once at the
bottom of the pan the will start to get warmer and become less dense. This
process will continue until the pan of water is at the same temperature.
Radiation
This is when the warm water particles vibrate the water particles next to them.
This will give them more energy and will make the water there warmer. The water
particles at the top of the can will radiate the heat energy into the
surrounding air. For heat to radiate it does not need to be in contact with
matter. Heat can radiate for some thing to another body through a complete
vacuum, this is how the sun heats up the earth. This process can also be called
the Wave Motion.
Evaporation
This could cool down the water, as when the water evaporates it will take the
heat away with it in the same way evaporating sweat cools down our bodies. If I
use a lid this could slow down this process. As the water vapour will not be
able to escape into the air as quickly as it would normally keeping the heat in
for longer.
If I insulate the can with different materials then it will slow down the heat
loss, but I cannot stop it. This will be useful for keeping drinks hot.
The materials that I could insulate the copper can that I will be using for my
experiment are:
Black paper
Corrugated card
Cotton wool
Tin foil
I also conducted my experiment without any insulation so I can compare the
results between insulated and non-insulated to find out if there is a distinct
difference in heat loss.Question to investigate What material/s offer the best protection against the cold, or, which material/s
is/are are the best insulators.Aim The aim of this investigation is to test three materials (wool, bubble
wrap, plain copper), and see which one/s are the best at keeping in the heat of
the hot water in the copper container.Factors There are many factors, which can affect
my experiment. The factors are:
If a lid is used, there will be a great difference in the speed of heat loss if
I use a lid. This is because a large amount of heat will escape form the top of
the container by convection and evaporation. Therefore if I use a lid it will
slow down these processes.
Also what the lid is made of will make a difference. If a lid is made of paper
or card then its insulation properties will be at a minimum, however if the
material used for a lid is polystyrene or bubble wrap then the heat loss
through the top of the container will slow down.Volume of water used When the volume of water is
higher, it will stay warmer for longer than if there was a low volume of water.
This is because when there is a high volume of water then the outside of the
water will cool down, but the inside will stay warm.If the container that the
water is insulated then it will stay warmer then if the container is not
insulated. This is because the insulation will slow down the process of heat
loss. If the container does not have insulation then the process will not slow
down.
If different types of insulation are used then this will affect the heat loss.
Materials of high insulation such as bubble wrap or cotton wool will not allow
much heat to be transferred through it, however materials of low insulation
such as black card will let the heat pass through it quicker. What
the container is made ofThe material of the
container could change the rate of heat loss. If it is made from polystyrene it
will not allow much heat to pass through it. If it is made of metal then it
will allow more heat to pass through it.
If the inside of the container is painted will make a difference. If it is
painted silver then it reflect some heat back to the water, but if it is
painted black it will absorb the heat and pass it out the other side. Room
temperature
If the temperature of the room is near the starting temperature of the water
then heat process of heat loss will not be as fast. This is because if there is
a bigger difference in temperature then the more heat will try to escape. Prediction
Out of the two materials that I chose to investigate I think that cotton wool
will be the best at reducing the heat loss. I am sa
cotton wool there are many small pockets of trapped air, and air is a very good
insulator in small pockets.
I also am suggesting that plain copper will be the worst insulator, because the
metal will allow the heat to run through it very easily resulting in a rapid
heat loss. I also think that with the
two insulators the rate of heat loss will start of fast and over time will slow
down. Plan
I intend to wrap two containers with the chosen insulators, but leave the last
one plain: Cotton wool Bubble wrapping I have also chosen to do a
control experiment without insulation to see if there is a great difference in
the heat loss if the container has insulation.
I will then boil some water and when it is boiled I will carefully pour it into
a measuring cylinder up the chosen volume (80cm³). I will pour it into the containers and allow it to
cool to the chosen starting temperature. Once it reaches the chosen starting
temperature then I will start the stop clock and record the temperature at
chosen intervals. I will repeat this procedure for the next two containers. I
will then repeat the whole experiment one more time to be sure that my results
that I will obtain are reliable and reproducible.To make this experiment a
fair test I will have to keep the following factors the same: Volume of water Starting temperature of water The number of times the insulation is wrapped
around the container Material of container Where the thermometer is placed in the water Be careful to protect eyes by using safety
goggles If I keep all of these the
same my experiment will be a fair one. Safety
Safety precautions are needed because I am dealing with hot water, which can
scald. The following things need to be acknowledged to, in order to keep this
experiment safe: Be careful not to knock over the container with
the hot water in Be careful not to knock over other peoples
containers Care is needed when pouring hot water Do not run with the container of hot water Apparatus
Below is a list of the things that I can use, whiles conducting my experiments: Three 150ml copper containers Kettle Safety goggles Stop clock 100 ml measuring cylinder Thermometer Corrugated card Cotton wool Bubble wrapping Method Put on safety goggles
2. Collect all the equipment that is needed as shown in apparatus list
above
3. Wrap the two containers with the chosen insulators, the third one is
left with no insulation
4. Boil kettle
5. Pour 100ml of boiled water into measuring cylinder
6. Pour this into one of the three containers
7. Put the thermometer in the water
8. Wait until the water cools down to 90°c
9. Start stop clock
10. Record the temperature every two minutes for 20 minutes
11. Repeat procedure for the other two containers
12. Repeat the whole set of experiment twice to ensure greater accuracy ResultsTest 1 Time
(mins) Temp
°c Temp
°c Temp
°c Cotton
Wool Bubble
Wrap Plain
Copper 2 82.0 86.0 82.0 4 78.0 84.0 79.0 6 72.0 82.0 76.0 8 69.0 81.0 72.0 10 68.0 78.0 69.0 12 65.0 76.0 67.0 14 62.0 75.0 64.0 16 60.0 73.0 62.0 18 59.0 70.0 59.0 20 58.0 68.0 56.0
Test 2 Time
(mins) Temp
°c Temp
°c Temp
°c Cotton
Wool Bubble
Wrap Plain
Copper 2 83.0 85.0 83.0 4 78.0 84.0 79.0 6 73.0 81.0 77.0 8 69.0 80.0 72.0 10 67.0 77.0 69.0 12 65.0 76.0 68.0 14 63.0 74.0 63.0 16 60.0 73.0 61.0 18 58.0 69.0 59.0 20 58.0 68.0 57.0 Average Results Time
(mins) Temp
°c Temp
°c Temp
°c Cotton
Wool Bubble
Wrap Plain
Copper 2 82.5 86.25 82.0 4 78.5 84.5 79.75 6 72.5 82.5 76.25 8 69.0 81.0 72.5 10 68.5 78.75 69.5 12 65.0 76.5 67.5 14 62.5 75.0 64.5 16 60.25 73.5 62.75 18 59.5 70.0 59.25 20 58.75 68.25 56.5 Conclusion
From looking at my graph and results table I conclude that there is a change at
the rate at which the heat transfers through the copper can. Altogether I
tested two materials and I have discovered which have the best insulating
properties. In order from the best insulator to the worst: Cotton wool Bubble wrap Plain copper In my prediction I had said
the cotton wool would be the best insulator, because it has many air pockets
trapped within it and air is an excellent insulator.I was correct in my
prediction.
From these statements I therefore conclude that: Heat loss is reduced when there is a insulator
wrapped around the container Small pockets of air makes a excellent insulator The colour black is a good conductor of heat Evaluation
I feel that I was precise when measuring volumes of liquid and the temperature.
I measured the water with a measuring cylinder and measured the liquid as the
liquid meniscus just touched the line.
Also I measured the temperature with a thermometer to the nearest .5 °C. I also measured the starting temperature
accurately.
I measured the time to the nearest second with the stop clock. Did I take enough readings?
I did take enough readings as I recorded the temperature once every two minutes
for 20 minutes, which gave me 10 results. I repeated the experiment once more
and calculated the mean average. This means I had 10 points for each insulator
used for the graph therefore it was much more accurate, so my graph was also
good. Anomalous results
I did obtain several anomalous results. These results may have been in error
because I may have recorded the time at slightly different times when writing
down the temperatures. Another reason for the inaccurate results is that I may
have moved the thermometer from the middle of the can slightly higher or lower
or a little bit to the left or right. Improvements to my experiment
As an improvement to my experiment I could have put a corkboard underneath the
copper container, as this will have reduced the conduction of heat from the
copper container into the table.
I could have used a clamp, boss and stand to hold the thermometer in a fixed
position; by doing this I could ensure that the thermometer is always at the
same place in the water.
By doing all of these it would have kept my experiments much fairer. ? ?????? By Dawan
Sharif 10Y ? ??????????????????????????????????????????????????????????????????????????????????????????????????????????????????