Thermal expansion - lab report PDF

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Thermal expansion 1. Presentation and organization a. Most materials expand when they heat up. ∆ l=α lo Δ T . linear expansion for the material. Length depends on lo ΔT .

α

is coefficient of

2. Introduction a. In this experiment, purpose is to measure α for copper, aluminum and steel. Three metal are isotropic which means that expansion is the same in all directions. Measure the temperatures. α would be independent of the absolute temperature.

3. Procedure Apparatues : expansion tube apparatus, steam generator, elevation block , digital multimeter, steel, Cu, and Al tubes, contriners for condensation.

Procedures 1. Measure the initial length of the tube and change in length of the tube while heating/ cooling. Measure lo to within 0.5 mm. 2. Measure a change in length on the gauge. 3. Attach the thermistor lug to the threaded hole with using a thumbscrew 4. Plug the leads of multimeter into the banana plug in the center of the expansion. Record resistance of the thermistor 5. Use a block of wood to raise the apparatus. 6. Turn the outer casing of the dial gauge to align the zero point on the scale 7. Record the change in length for the tube. Connect the steam generator the copper tube. 8. Turn on the steam generator. When the thermistor resistance stabilizes, record the resistance. Repeat the experiment with copper, steel and aluminum tubes. ℃

Data

Copper L(mm)

Aluminu m

steel L(mm)

℃

R

0.8

10.7

82

0.75

11.74

80

0.7

13.03

78

0.65

14.68

74

0.6

16.54

70

0.5

18.85

68

0.5

21.1

65

0.45

25

61

0.4

29.1

57

0.35

34

53

0.3

40.2

49

0.25

47.2

45

0.2

56.1

42

0.15

67.3

38

0.1

84.2

33

0.05

84.4

29

℃

R

L(mm)

℃

R

60

9.59

84

119

9.4

84

55

10.9

82

110

9.86

83

50

11

80

105

9.5

82

45

12.5

76

100

10.08

80

40

14

73

95

10.67

78

35

16.5

68

90

11.31

76

30

19

64

85

12.12

74

25

23

59

80

13.06

72

20

28.5

54

75

14.05

70

15

35.9

48

70

13.18

68

65

16.68

65

60

18.296

62

55

20.3

60

50

23.2

58

45

24.7

55

40

27.5

52

Copper 0.9 0.8 0.7

f(x) = 0.01 x − 0.37

L

0.6 0.5 0.4 0.3 0.2 0.1 0 20

30

40

50

60

70

80

90

Temperatures

steel 0.7 0.6 0.5

f(x) = 0.01 x − 0.46

L

0.4 0.3 0.2 0.1 0 45

50

55

60

65

70

75

80

75

80

85

90

Temperatures

Aluminum 1.4 1.2 1

f(x) = 0.02 x − 0.83

L

0.8 0.6 0.4 0.2 0 50

55

60

65

70

Temperatures

85

90

Formula is

∆ l=α lo Δ T .

Kx∗bex

Y=

lo

In this experiment, constant value of For copper, k was 0.0138 K =

α

For steel K was 1.2139 so

α

α=

|

= 1.94∗10−5 (K−1 )

α

(K−1 ) So

|

1.94∗10−5−17∗10−6 17∗10−6

0.012 710❑

=

α

* 100 = 14%

= 1.69∗10−5 (K−1 )

t heor et i cal Val ueofst eel i s= 12∗10−6 (K −1 )

experimental−theoretical Theoredical value

=

|

1.7∗10−3−12∗10−6 12∗10−6

For aluminum K was = 0.0229 so α = α

0.0138 710❑

−6 t heor et i cal Val ueofcopperi s 17∗10

=

K lo

is 710mm

α lo so α =

experimental−theoretical Theoredical value

α=

K = α lo

0.0229 710❑

=

|

α

* 100 = 40.84%

= 3.22∗10−5 ( K−1 )

t heor et i cal Val ueofal umi num i s= 24∗10−6 (K−1 )

experimental−theoretical Theoredical value

=

|

−5

−6

3.22∗10 −24∗10 24∗10−6

|

* 100 = 34.39%

Part 2 question 2. Er r orper cent agef orcopperwas14%.St eel was40. 84% andAl umi num was 34. 39%.Amongt hr eemet al s,copperper cent agewasl owestwhi chwas14%. St eel andAl umi num washi gh. 3. To improve experiment accuracy, make the material dry before experiment started. If material is not dry, it might affect experiment data so that data would not be accurate. 4. B = 3 α 5. Bimetrallic strip contracts or expands the pointer which moves up and down.

6. It does not affect the data

4.Resul tanddi sc us si on Er r orper cent agef orcopperwas14%.St eelwas40. 84% and Al umi num was34. 39%.Amongt hr eemet al s ,copperper cent age wasl owestwhi c hwas14%.St eel andAl umi num washi gh.Room t emper at ur esc oul dmak eer r orbecausei fr oom t emper at ur ecol d,i t c oul dmak et hemet al cool .Met al ss houl dbedr ybef or eexper i ment s becaus ei fmet al sar enotdr y ,i tc oul daffectt hedat a.Thegauge k eepmovi ng,i ti shar dt oseet henumbercor r ect l y ,s oi tc oul dbe mayhumaner r or s .Meas ur ement sandappar at uswer enotac c ur at e, s oi tc oul dc r eat eer r or s .Labr esul twasas uc c es sev ent hougher r or . Wedet er mi nedhowdi ffer entmet al sex pandi ndi ffer ent t emper at ur es ....