Physics Investigation: How does insulation effect the loss of heat

To make this a fair test I will have to do the following. I will keep the volume of water the same. I will wrap the beaker with newspaper in the same way each time because some ways can effect the heat loss more that others. I will place the thermometer in the beaker at the same place each time. I will place the beakers on polystyrene when they are being tested because it insulates the heat. I will use the same type of newspaper for each experiment. I will use the same size beaker, which is made out of the same material. The factors I will change are. I will change the layers of newspapers on the beaker.

I will get 6 beakers. I will record two at a time. I will put polystyrene on the top and bottom of the beakers when I have filled the beakers up with 150 ml of boiling water. There is a little hole in the polystyrene on the top of the beaker to stick the thermometer through. I will then take results every five minutes for a total of 30 minutes. There will be 6 readings taken for each newspaper layer range. I will record 6 different layers. 0 layers, 5 layers, 10 layers, 15 layers, 20 layers and 25 layers. This should give me a good range of results.

I predict that the more layers of newspaper round the beaker, the less quickly the water will lose heat. I say these because the more layers there are the more air pockets there are to keep the heat in. If there are more air pockets the more hot air is trapped in the newspaper. This air acts as an insulator. I also predict that more heat will be lost at the start of the experiment because the water is hotter, so there is more of a heat difference between the inside and outside. Therefore, more heat is conducted out the beaker because of the cooler temperature outside the beaker. But as the temperatures even out the heat loss gets less, because less heat is being conducted away from the beaker. So you should see a graph looking like this.

Results:

(Temp in C)

Minutes

0 layers

5 layers

0 layers

5 layers

20 layers

25 layers

77

78

76

78

76

77

2

76

76

75

77

75

76

3

74

75

74

76

74

75

4

73

74

73

75

73

75

5

72

73

72

74

73

74

6

70

72

71

74

72

73

7

69

71

70

73

71

72

8

68

70

70

72

70

71

9

67

69

69

71

69

71

0

66

68

68

70

68

70

1

65

66

67

69

68

69

2

64

66

66

69

67

68

3

63

65

65

68

66

67

4

63

64

65

67

65

67

5

62

63

64

66

64

66

6

61

62

63

65

64

65

7

60

61

62

64

63

64

8

59

61

61

63

63

63

9

59

60

60

62

62

62

20

58

59

59

61

62

62

21

57

59

58

60

61

62

22

56

58

57

60

60

61

23

55

57

57

59

59

60

24

55

56

56

58

58

59

25

54

55

55

57

58

58

Analysing evidence and conclusion:

My results went down in a good trend. All apart from the 25 layers which cooled quicker than the 20 layers. All the results are clear that they gradually decrease in the graph, In a fairly straight line. The more they are insulated, the slower the temperature falls. It is because the newspaper traps air in between it and the beaker, this insulates the beaker and traps hot air from escaping.

Evaluation:

My results were good. I conclude that the more layers around the beaker, the slower the temperature falls. I could have measured the results more accurately, by taking more time and recording each result twice but I didn't have time.

By William malbon.

Physics coursework.doc - 2 - 20/03/02