Human Sized Spectra
(LO1-Rec1b)
Name ___________________________________________
You can earn 15 points for participation in this activity. Turn in your responses to the numbered
items at the beginning of this week's laboratory.
A spectrometer is a device that can be used to determine, very precisely, the individual
colors that make up light coming from any source. You will use a spectrometer in the
laboratory later this week, and today's activity will allow you to explore how a
spectrometer works.
The most important part of a spectrometer is the diffraction grating. A diffraction grating is
made from a material that has been etched with many tiny lines. (The diffraction grating
film that you will use today has 196 lines / mm.)
1. Which colors are bent most and which least - make a list, in order of increasing angle of
diffraction.
We'll work out as a group how to design the human-sized spectrometer. We will line up
along the front of the room to represent the location of the different colors of light as they
would appear after passing through a diffraction grating at the back of the room.
2. Make a sketch of the strings and light source from the human-sized spectrometer.
Identify and label all relevant angles and observations.
3. What could be done to improve the accuracy of this experiment? Describe as many
different ideas as you can think of, and explain (briefly!) why you think they would
improve the results.