To investigate the effect of insulators on the rate of cooling

September 13, 2017 September 1st, 2019 Free Essays Online for College Students

Introduction: I will be investigating the rate of cooling, by using various numbers of layers of insulators round a beaker of hot water. The science which effect my investigation are as follows:

Conduction is a transfer of heat energy through a substance from the hotter region to the cooler region without any movement of the substance itself. As the substance is heated, free electrons spread through the substance bumping into other electrons and passing on Kinetic energy. Gradually energy is transferred along the substance. Radiation is the transfer of heat energy through waves. Hot objects emit mainly infrared radiation which can pass through a vacuum i.e. No medium is needed for its transfer. How much radiation is given out or taken in by an object depends on its surface

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In this experiment I could have many variables. Ranging from colour to size. They are:

– The material of my cup (ceramic, metal, glass, polythene, plastic)

– The layers of insulators (no layers, layer, layer etc) [this is what I have chosen to use as my variable]

– Different types of insulators (wool, bubble wrap, foam, cotton, paper)

– Different colours of insulators. (Black, transparent,)

Prediction:

I predict that when I change the amount of layers of polystyrene around my beaker, the more layers there are the slower the rate of cooling will be. So, therefore the fewer numbers of layers I use the quicker the rate of cooling.

This is what I think will happen. Because I am using ‘polystyrene’ as my insulator the ‘more polystyrene I use the more air will be trapped. So, when the high temperature from the water tries to escape the ‘trapped air’ will act as a barrier and will hold in as much as possible. So, therefore the rate of cooling will be very less.

I think this will happen because as the beaker is made of copper, which is a good conductor, the high temperature of the water will reduce rapidly.

Diagram:

Plan of Experiment

Apparatus I will use in this experiment:

– Electric water kettle

– Measuring cylinder

– Thermometer

– Copper beaker

– Insulator (polystyrene)

– Stop-clock

Method:

– Boil the water in an electric kettle.

– Pour the water into a measuring cylinder. And measure until ml.

– Pour the water into the copper beaker

– Put in a thermometer and measure starting temp

– Put on the timer. So that you can“

– And note down the temperature every 1 minutes. Until 10minutes.

In this experiment I will be measuring the temperature drop every one minute. I will do this by having a stop-clock to measure the temperature at exactly two minutes each time.

Safety:

In this experiment I will be handling hot water. So, I could have several different types of accidents. Like for example:

– The hot water could spill on to someone which can lead to them burning themselves or even worse. So, I must make sure that when carrying out my experiment no one is sitting down on a chair. All chairs are tucked in. Bags are in the cupboards and there is nothing that anyone could trip over from.

– When pouring the water out into the basin after conducting the experiment the beaker will be extremely hot! (Near boiling point) So if I handle it by hand then I could burn myself, or I could drop the water causing the water to either spill onto someone, or it could spill onto the floor and someone could easily trip over it and hurt themselves.

Variable & Fair test:

There will only be ONE thing that will change throughout the entire experiment. This will be the amount of layers around the beaker.

I have to make sure nothing changes except my variable. So everything else has to be kept the same to make this a fair test. The things I will have to keep the same are:

– The amount of water used

– The temperature of water

– The insulator material must always be ‘polystyrene’

Results:

No of layer

Start temp

Temp after every 1 min

Temp after every 1 min

Temp after every 1 min

Temp after every 1 min

Temp after every 1 min

Temp after every 1 min

Temp after every 1 min

Temp after every 1 min

Temp after every 1 min

Temp after every 1 min

1

87

84

82

80

78

74

73

72

72

70

69

2

86

80

82

82

86

78

76

74

73

72

70

3

91

89

86

84

83

79

78

76

74

74

72

4

91

88

86

84

83

81

80

76

76

75

75

Conclusion:

The shape of the graph is a curve. As the amount of time (every 1 minute) increases, the rate of cooling decreases. What I mean by this is that as the amount of layers increases the temperature of hot water drops down steadily. This is the usual shape you get when things tend to cool down. The ‘X’ axis is the Time every two minutes. The ‘Y’ axis is the temperature in ?c. When things are hot they cool down very fast. But, the more insulators there is around the substance the longer it takes to cool down. Therefore, when I use four layers of polystyrene it took longer to cool down. Whereas when I have less no layers of polystyrene the quicker it cooled down.

Looking back at my prediction I see that what I had predicted was exactly right. The beaker with less layers of insulation had dropped at a very rapid speed. Compared to the beaker with four layers of insulation. Which dropped at a slower speed. The principle was exactly the same.

The beaker that had no layers on insulation would take in the high temperature, and because the beaker was made of metal it was a good conductor of heat energy so the heat would escape very quickly. Whereas the beaker with lots of layers would help keep the high temperature within itself. And stop it from escaping. This is because of as the number of polystyrene increased there was more air trapped just like a double glazed window or door there is air trapped in between the glass

Evaluation:

My experiment did not go as I had planned. My graph tells me that some of my results were fairly accurate. But a few of my results were not accurate results. I can tell this from my graph by looking at the bar chart, where it is much clearer to see the difference in temperature every one minutes. If you look closely at the line graph you will notice that at one minutes the temperature of the ‘one layer’ was slightly above the beaker with’ two layers’. This cannot be right because the beaker with 1 layer should drop down in temperature quicker then the beaker with 2 layers. Because the beaker with 2 layers has more insulation around it. This could be because we didn’t take down the results properly or my average wasn’t right. I tried to make my results accurate by making sure everything that I do was a fair test.

I could improve my investigation by, like I said before conducting my experiment more than once, so that I can take out a reliable average. Also this would help us to draw out accurate conclusions.

My method was good. It was quick, simple and easy to follow by. Especially once we got use to how to do it.

I think that my conclusion is very accurate. I drew my conclusion out of previous knowledge, textbooks, class notes and by doing this investigation. I had enough evidence to help draw up this conclusion. To help get even more evidence for my conclusion I could do another type of investigation similar to this.

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