Investigation To See How Conduction Affects Heat Transfer

* Cover the top of the calorimeter to minimise convection.

* The only variable that needs to be changed are the layers of carpet jackets.

Equipment

What apparatus will you be using?

A copper calorimeter

Water

Kettle

Carpet Jackets

Thermometer

Lid

Method

. Using a cooled calorimeter, add a set amount of hot water. Take a starting reading from the thermometer. Put a carpet jacket on the calorimeter and start the clock.

2. Measure the temperature every minute for 13 minutes.

3. Repeat with other jackets, having cooled the calorimeter down before adding the water.

Range of Results

What results do you intend to take? How often will you take them? Over what length of time?

The results I will be taking will be a measure of how much heat the calorimeter is losing. I intend on taking three sets of results for each layer and then taking the average. I will take a time reading every minute for 13 minutes.

Prediction Linking to Theory

I predict that with one layer, the heat will be transferred faster than with two or three layers. The time taken to heat will increase with every layer added.

This is because the layers act as insulation and the carpet has air pockets within it. Air is a good insulator and the more jackets added, the higher the amount of trapped air, and so the heat won't be transferred from the calorimeter as quickly. However, heat will still be convected, but the convection currents will stay inside the carpet jackets.

Conduction will occur within the copper calorimeter because when the hot water heats the calorimeter, it does so by vibrating water particles, which in turn gives the bonds between the copper calorimeter particles energy, making them vibrate and heating them. Air is an insulator, so the air particles cannot be given energy to vibrate, as the bonds are not strong enough. Instead, the air traps the heat.

The air traps the heat and does not pass on the energy because conduction only occurs in solids. Conduction only occurs in solids because the particles are linked together by strong bonds, and conduction works by making these bonds vibrate by passing on energy. Air is a gas and gas particles are not linked by bonds, so they can only pass on kinetic energy by a much slower method known as convection, which is particles bumping into each other.

Preliminary Experiment

Possible time (secs)

0 layers

layer

2 layers

3 layers

0

83

78

75

85

30

83

76

73

83

min

81

74

73

82

:30

80

75

72

81

2 mins

79

73

71

79

2:30

78

73

70

78

3 mins

72

71

70

78

Possible time (min)

0 layers

layer

2 layers

3 layers

0

87

78

75

83

81

74

73

82

2

84

73

71

79

3

83

71

70

78

4

82

69

70

76

5

80

68

67

74

6

78

66

66

74

For our final experiment, I will use the time span of 1 minute, as it seems more accurate and it allows time for convection and conduction to take place sufficiently.