Controlled Variables:
Introduction:
-Room temperature
-Distance from where will be recording thermal image
(1metre)
-The same type of lamp we put the bulbs in
-Same power source
-The spot of where we measured the heat( different parts of
the bulb may have different temperature)
- The different types of light bulbs we use
The main aim of our experiment is to judge the
efficiency of Fluorescent, Incandescent and Halogen
light bulbs which are regularly used in households. We
will achieve this data by using the thermal camera to
measure the temperature or heat energy released by
each individual bulb . By knowing the amount of heat
projected by the bulbs we will be able to judge its
efficiency as the energy left is projecting light.
Hopefully we can conclude which bulbs are worth your
money.
Problems we faced:
Hypothesis:
-Finding the specific heat capacity of the filament of the
bulbs
-Deciding between 2 equations : We chose the thermal
energy equation that included specific heat capacity of the
bulb as the other one included surface area of the bulb and
we felt as an estimated result this would limit our final
outcome.
We predict that the halogen light bulb will prove the
most efficient in terms of emitting the light at the lowest
temperature.
Method:
We set up a thermal camera to accurately measure the
temperature of our light bulbs throughout our
experiment. First we set the camera a metre away from
the lamps and recorded the initial temperature of our
light bulbs. We then recorded the temperature rise once
the applicants where turned on after every minute up to
10 minutes. We repeated this experiment once the bulbs
can cooled down and calculated an average and then an
average of the mean temperatures. Then used the
equation : E = m × c × θ to determine the thermal
energy so that we could subtract this from 100 to
estimate the efficiency of the light energy of the bulbs.
Average Temperature of Light Bulbs across 10 minutes
Fluorescent Bulb
120.0
Incandescent
100.0
Halogen
80.0
60.0
Fluorescent
40.0
20.0
0.0
0
2
4
6
8
10
12
14
Blackbody:
J.Ababio-Danso, M.Dodds & P.Tharmathas
We presumed that all of our bulbs were black body
materials so that we could measure the
temperature. This means that they are
insulated, enclosure and therefore in thermal
equilibrium.
Halogen Bulb
Incandescent Bulb
Time
(Minutes)
0
1
2
3
4
5
6
7
8
9
Reading
1 (°C)
27.7
50.1
58.7
62.6
63.3
64.4
65.0
64.7
63.0
62.7
Reading
2 (°C)
28.0
45.7
54.4
56.5
58.0
58.2
62.9
65.9
66.8
66.8
Average
(°C)
27.9
47.9
56.6
59.6
60.7
61.3
64.0
65.3
64.9
64.8
Reading
1( °C)
29.4
42.3
55.5
65.0
70.0
73.5
75.1
77.5
77.3
77.7
Reading
2 (°C)
28.2
41.6
53.2
61.1
67.1
70.8
72.8
75.1
75.2
77.0
Average
(°C)
28.8
42.0
54.4
63.1
68.6
72.2
74.0
76.3
76.3
77.4
Reading
1 (°C)
28.6
85.0
101.5
107.0
111.5
112.2
113.0
114.0
115.2
114.7
Reading
2 (°C)
27.9
52.7
62.8
70.7
73.9
75.4
79.1
80.2
81.5
82.2
Average
(°C)
28.3
68.9
82.2
88.9
92.7
93.8
96.1
97.1
98.4
98.5
10
59.3
66.7
63.0
77.0
78.1
77.6
115.5
82.5
99.0
FINAL RESULTS
Light Bulb
Efficiency
Incandescent
74.4%
Fluorescent
75.3%
Halogen
80.7%