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Student Worksheet: Identifying Light Energy by Temperature
Changes
Procedure
- As illustrated in the diagram set up your apparatus. Straighten
out the paper clip and carefully thread the peanut onto the paper clip.
You want to avoid as much as possible cracking the peanut.
- Measure out 50 ml of water and pour the water into the flask.
Determine the mass of 50 ml of water. Record the initial temperature of
the water.
- Place the small aluminun pan with peanut underneath the flask with
the water in it. Using a match, light the peanut and allow it to burn.
Make sure the apparatus is closely set up so that a large amount of heat
is not lost into the air.
- Record the final temperature of water after the peanut has
stopped burning.
- Answer the Think About questions on paper.
Think About
- Describe what happened to the final temperature of water
and explain why.
- The energy emitted from the peanut is mostly infrared light (heat).
Review the electromagnetic spectrum diagram. What would happen to
the temperature of the water if the peanut were to emit the same number
of photons but as ultraviolet light? Hint: Compare the energy of
infrared and ultraviolet light.
- Explain how you could use the temperature change of the water to
create a spectrum of the light energy released by the burning
peanut.
- Relate this experiment to how a microcalorimeter works.
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