E-M Spectrum Lab: Collecting Data from Stars and Planets
Integrated Science 2
Name:
Date:
Period:
 Background
Gathering and studying starlight is just one way that we learn about the universe. Visible light is only a small
part of the electromagnetic spectrum, which covers all forms of radiation. By studying different types of radiation
we learn more about both the visible and invisible parts of the universe.
The electromagnetic radiation travels through space as waves of varying length (the distance between wave
crests). Gamma rays have the shortest wavelength, then X-rays, and so on through the spectrum to the longest
radio waves. Visible light, which is all that we can see naturally, occupies a very narrow portion (less than
0.00001 percent) of the spectrum.
Glowing solid objects like the hot filament of an electric light, molten metals, and hot compressed gases deep
inside a star give off a mixture of many wavelengths of light, called a continuous spectrum. When chemical
elements occur in the form of gases, their atoms give off a different kind of spectrum, called the bright-line
spectrum. This information can be used to identify elements the same way as a fingerprint is used to identify a
person.
A dark-line spectrum forms when the light from a continuous spectrum passes through a cooler gas (like the
gas surrounding the sun or stars). The dark-lines are in exactly the same the same place as the bright lines from
the same element in a bright-line spectrum, which indicates which element is present. The dark-lines are referred
to as absorption spectrum. The absorption spectrum from a star or planet shows the composition of the star’s outer
layer or the planet’s atmosphere. When the dark lines are matched with bright-line spectra, the elements in the
sun’ can be identified. There are 80 elements in the sun’s atmosphere.
In this lab, spectroscopes or a special refracting film will be used to collect data about the bright-line spectrum
of different elements and gases. These spectra will be compared to the absorptions spectrum to identify stars.
 Background Questions:
1) What types of radiation make up the electromagnetic spectrum?
2) What type of energy can give us information about space?
3) How do scientists determine the elements present in a star?
 Procedure Part 1
1. Observe each light source provided through spectroscopic film.
2. Draw the banding patterns and label the colors of the continuous spectra for each light source.
3. Record the name of each single-element light source.
4. Answer the “analysis and conclusion” questions then continue to Part II.
 Data Part 1
Ex. 1 – Continuous Spectrum from “white” or visible light.
Ex. 2 – Known Element A
Element Name:
Ex. 3 – Known Element B
Element Name:
Ex. 4 – Known Element C:
Element Name:
Ex. 5 – Known Element D:
Element Name:
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E-M Spectrum Lab
 Analysis and Conclusion
1. Describe the visible part of electromagnetic spectrum by using the terms “wavelength, frequency, and
energy.”
2. How are atomic spectra used by astronomers to find out what stars, clouds of gases and planetary atmospheres
are made of?
3. Explain the differences between a continuous spectrum, bright-line spectra and absorption spectra.
4.
Draw the spectrum of a star made only of helium that is moving away from us (that is Redshifted)
 Procedure Part 2
Worksheet 2 shows the absorption/black-line spectrum of 5 different stars.
1. Using the worksheet 1 overhead transparency as an overlay, determine which elements are present in each of
the 5 stars.
2. When finished, answer the following questions.
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E-M Spectrum Lab
 Data Part 2
1. For each star, check the boxes of the elements that can be found in the spectrum.
Hydrogen
Iron
Neon
Sodium
Lithium
Star 1
Star 2
Star 3
Star 4
Star 5
Magnesium
Helium
2. Which of the elements are found in each of the five stars (which elemets do all the stars have in common)?
3. Look at your element data for Star #4. What can you assume about Star 1 based on the elements it contains?
4. Look at your element data for Star #2. What can you assume about Star 2 based on the elements it contains?
5. Why do you suppose that all five stars contain hydrogen and helium?
6. What are some characteristics of stars that might account for the fact that some have more complex elements
in the spectra?
7. Draw the absorption spectrum of star 4 as if it moving toward us.
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E-M Spectrum Lab