U60040 Heat
Work sheet
Experiment 7 Radiation of heat
Topics covered in the experiment
• Heat is given out by a hot body to its surroundings.
• The heat can be transported without any medium to carry it, in the form of heat radiation.
• The heat radiation is distributed in all directions and can be reflected and focused.
• A body irradiated by heat radiation gets heated.
Parts required:
From the Student Kit – Thermodynamics (U60040)
1 spirit lamp
1 mat
1 thermometer
1 concave mirror
From the Student Kit – Basic Set (U60011)
1 base plate
2 support plate
2 support rod, l = 100 mm
2 slotted double clamps
1 retaining clip, d = 8 mm
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Heat / Experiment 7 Work sheet 3B STUDENT Kit
Setup
Figure 1
1) Mount the support base on the middle and in the right bore holes of the base plate (see Figure 1), by inserting the screws through the bore holes from below and screwing it to the support base from above.
2) Insert the support rod till the stop point into the support bases and stop it using the screws.
3) Fasten one double clamp to the left support rod that the free bore is facing right.
4) Fasten the retaining clip to the double clamp.
5) Insert the thermometer through the retaining clip, from top.
6) Place the spirit lamp on the mat, a little to the left of the support rod, so that the flame is about 5 cm from
the thermometer.
7) Adjust the height of the thermometer so that its tip is at the same height as the flame.
8) Fasten the second double clamp to the right support rod that the free bore is facing forward.
9) Fasten the concave mirror vertically in the double clamp and orient it so that its center is at the same
height as the tip of the thermometer, and it is about 1.5 cm from the tip of the thermometer.
Procedure
1) First remove the concave mirror together with the double clamp from the shorter support rod.
2) Read the room temperature from thermometer and note down the measured value in the measurement
table.
3) Light the spirit lamp and adjust the flame height so that it is optimal.
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Heat / Experiment 7 Work sheet 3B STUDENT Kit
4) Observe the thermometer and note down the temperature shown in the measurement table once the display does not show any further increase.
5) Again fix the concave mirror next to the tip of the thermometer and observe the thermometer.
6) Note down the temperature shown in the measurement table, once the display does not show any further
changes.
Measurement table
Room temperature
without the concave mirror with the concave mirror
Temperature at the tip of the thermometer
21°C 26°C 32°C
Examine and explain the observations:
a) Compare the temperature recorded when the spirit lamp is burning, with the room temperature.
If the spirit lamp is lit, the thermometer records a higher temperature.
b) How can this difference be explained?
The spirit lamp gives out heat in all directions. One part of this heat is recorded by the ther-
mometer. That is why the thermometer shows a higher temperature.
c) Compare the temperature measured with the concave mirror placed near the tip of the thermometer, with
the temperature recorded without the concave mirror.
If the concave mirror is placed near the tip o
f the thermometer, the thermometer shows a higher temperature.
d) How can this difference be explained?
The concave mirror reflects heat to the tip of the thermometer, which would not have been re-
corded by the tip of the thermometer without the concave mirror.
e) In what form is the heat transmitted?
The heat is transmitted in the form of heat radiation.
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