OBSERVATION
Results
HYPOTHESIS
Heat energy transfer is the process by which heat energy is exchanged between bodies or parts of the body at different temperatures. Heat energy is generally transferred by convection, radiation, or conduction.
Conduction is the transferring of heat energy through any kind of material. Some materials are good conductors and some are bad conductors. For example, metals are good conductors. But wood is a bad conductor. This is because wood can absorb which separates the atoms further apart. Bad conductors are called good insulators. People use wooden spoons in cooking, because heat energy cannot travel through the wooden spoon very easily.
Metals are good conductors because the atoms are structured in a way that atoms can vibrate one another easily. Kinetic energy is transferred to cooler parts of the metal by free electrons as they diffuse through the metal, colliding with ions and other electrons. This happens to copper when it is heated at end.
Liquids are not so good conductors as solids because the atoms are constantly moving around so the atoms do not vibrate one another as well. There are also fewer atoms in liquids. For example Mercury.
Gases are good insulators because there are a few atoms and the atoms are spread over a vast area which makes the process of vibration very difficult.
Convection is the transferring of heat energy in liquids and gas. There are 5 steps to the way in which convection works. They are:-
- Firstly, air warms up and becomes less dense.
- Then, warm air rises.
- Later, the air cools and becomes denser.
- After, this denser, cooler air now sinks.
- Finally, this cooler air now replaces the air which is rising.
This is the how ...
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Gases are good insulators because there are a few atoms and the atoms are spread over a vast area which makes the process of vibration very difficult.
Convection is the transferring of heat energy in liquids and gas. There are 5 steps to the way in which convection works. They are:-
- Firstly, air warms up and becomes less dense.
- Then, warm air rises.
- Later, the air cools and becomes denser.
- After, this denser, cooler air now sinks.
- Finally, this cooler air now replaces the air which is rising.
This is the how heat energy moves in convection.
Radiation is the transferring of heat energy by waves with no particles being involved. Hot objects send out mainly infrared radiation, and the hotter the object, the energy it radiates. How much radiation is given out or taken in by an object depends on its surface
In the experiment, we going to test how fast heat energy is lost through a steel can. Before proceeding with the experiment we must find out where heat energy is being lost in the can. If we do this then we can prevent every section of losing heat energy.
- Heat energy is being lost by the side and bottom of the can by conduction because the energy from the water vibrates the molecules in the metal can.
- Heat energy is being lost from the gap of the lid by convection because the energy in the water heats the air molecules which expands and rise but then cools and the heat energy is released into the air.
- Heat energy is being lost by the side of the can by conduction and convection because the heat energy is being passed through the steel can, then through the bubble wrap and then through the air in the bubble wrap. Finally the heat energy is then conducted through the other end of the bubble wrap.
- Heat energy is being lost in the space between the lid and the water by convection because heat energy in air is being warmed up, then cooled and finally the air sinks.
Unfortunately, we cannot stop conduction or convection because heat energy can escape in one way or another. So we cannot eliminate any of these heat energy losing problems. We can only put a material around the can to slow down the process of conduction. If we had a solution of stopping heat energy from traveling then there would not be any point of doing this experiment.
We shall be using one type of material but in two sizes. We shall be using bubble wrap. One bubble wrap will have big bubbles on it and the other will have small bubbles on it.
What will happen to the heat energy is that it will escape from the sides and the bottom of the can and then through the bubble wrap. The bubble wrap will be a better insulator depending on its size. I think the big bubble wrap will be a better insulator than the small bubble wrap because the big bubble wrap has a gas in its bubbles and this makes heat energy hard to escape, as there are fewer atoms in gases than solids and liquids.
Heat energy takes longer to escape in gases than solids and liquids because the atoms in a gas are far apart so heat energy cannot vibrate an atom to another.
Prediction
From my research, I predict that the big bubble wrap will be a better insulator than the small bubble wrap because there is a lot gas in each bubble preventing heat energy from escaping so easily. I think the plastic bag will not be as good of an insulator as the bubble wrap because the plastic bag will be very close to the steel can. This will let heat energy just go through the steel can and the plastic bag.
PLAN
Apparatus
- Kettle
- Water
- Measuring Cylinder
- Steel Can
- Thermometer
- Plastic Lid
- Stop Watch
- Big Bubble Wrap
- Small Bubble Wrap
- Small Plastic Bag
What are we going to do?
We are going to experiment for which bubble wrap or bag is the best insulator. We are doing this experiment because to prove my research in the hypothesis. We will test the big bubble wrap, small bubble wrap, a plastic bag and just the steel can. To extend the experiment we will test the bubbles facing inwards and outwards of the steel can. This will be used for the big bubble wrap and small bubble wrap.
- First we will boil up some water in a kettle.
- Then, we will measure the 140ml in a measuring cylinder. This is because we won’t to know how easily heat energy can escape through the can.
- We shall pour the 140ml of hot water on the steel can.
- We will put a plastic lid on top of the can. A thermometer will be put through a pierced hole into the middle of the plastic lid.
- Later we will measure the temperature.
- As soon as the temperature falls to 84 degree, we will start the timing.
- We will record the temperature every minute for 10 minutes. After ten minutes the experiment will be done.
- We will repeat the experiment to find an average temperature for every minute.
- Finally we well repeat this experiment for the big bubble wrap facing in and out of the can, the small bubble wrap facing in and out of the can and the plastic bag around the steel can.
We have chosen to start every experiment at 84 degrees because we think the water may not reach temperatures as high as 90 degrees.
For a fair test we will measure the temperature at every minute to make equal spacing of time between each reading of time.
ANALYSIS
Apparatus
- Kettle
- Water
- Measuring Cylinder
- Steel Can
- Thermometer
- Plastic Lid
- Stop Watch
- Big Bubble Wrap
- Small Bubble Wrap
- Small Plastic Bag
Method
In my experiment I kept many of the things I was going to do, the same. But after finding a couple of difficulties in the experiment I had to alter a couple of things. They were: -
- The process of measuring the hot water. I found out that the temperature of the water decreased rapidly so I could not start the experiment at 84 degrees. So I changed the process of measuring the water. Instead of measuring the water after boiling it up, I measured the water before boiling it up. This meant that I had to put 5ml of extra water in the kettle because a tiny bit of the water would have been evaporated.
- Inserting more water into the steel can. I found out that the steel can was not being filled to the top. This meant that the air between the lid and water had been transferring heat energy by convection. I stopped this by adding 10 extra millilitres of water into the steel can.
Conclusion
In my results table I have observed that the big bubble wrap was the best insulator. The small bubble wrap was a worse insulator than the big bubble wrap and although the plastic bag was the worst insulator, it was the best insulator. The results of the experiment with no covering on the steel can did not fit the graph. This is because the graph showed that the experiment with no covering on the steel can was a good insulator. I would have thought that no covering on the steel can would have helped the heat energy escape. The only explanation for why the graph showed that the experiment was a good insulator is that a big, thick object would have been near the steel can preventing from escaping so easily.
In my prediction, I said that the big bubble wrap would be the best insulator. This is because there is a lot gas in each bubble preventing heat energy from escaping so easily. The atoms in a gas are little and very spread out which makes the vibration of one atom to another very hard.
I also said that the plastic bag was a good conductor because the heat energy only had go through the steel can and plastic bag. There was not much gas between the steel can and plastic bag together because the plastic bag was close to the steel can. Heat energy can go through a solid easily by conduction because the atoms are close together making the vibrating of each atom easy. This theory has been proved by my results and graph.
I decided to record the temperature at every minute in each the experiment, because then I would have a wide range of results of the temperature decreasing.
EVALUATION
There were some things that were not fair which made the experiment go wrong a little. They were:-
- The reading of the temperature. Sometimes I would not reading the temperature because the marks on the thermometer were squashed together so I could not read the numbers so easily. If I had a high-tech piece of equipment (e.g. a computer) then I could connect a thermometer to the computer and just read the temperature off the computer.
- The reading of the temperature APPROXIMATELY every minute. Most of the time I could not read the temperature exactly every minute. Sometimes I was reading the temperature before the minute and sometimes after the minute. This effected my results because some results read the same and some had a big decrease (like the point at the orange circle). I could get solve this problem by also using a computer and connecting a stopwatch to it so the temperature could be given at exactly every minute.
- The rounding off of a number after being read. Many of the numbers that I read were not whole numbers. So I had to result to rounding the number off. This effected my results because again some results read the same and some had a big decrease. If the thermometer had smaller marks telling you the numbers then I could have precise results. We could result to using a computer.
I was not happy with my results with my results for “no covering” at 1 minute (marked orange circle) because of all the reasons above. These reasons are why my graph a bit out of shape.
Although my graph was not accurate, my results were reliable to prove my prediction. My results clearly show that the big bubble wrap was the best insulator (and a bad conductor) and the experiment with the bag was the worst insulator (and a good conductor).
I could make my results better by repeating the whole experiment again but this time using all the suggested I have given. If I were to do this then I would get the accurate results and prove that the experiment “without covering” would be the worst insulator. I would do the experiment three or four times to get a better and more reliable average.
My results are not sufficient to prove my conclusion. I think I would have to do the experiment with “no covering” again to at least make my conclusion right.
