GEMS ‐‐ Spectroscopy and Space Experiment In this experiment, you will build a spectrometer in order to collect emission spectra on 5 different light sources. You will compare your data to a collection of emission spectra for all elements in the periodic table to identify what elements are in the different light sources. 1. Build spectrometer 2. Use the diffraction grating to observe the color of each lamp. This can be tricky! In order for it to work, the room will have to be completely dark (in order to block out other light sources) and the students will have to be close to the flame, holding the diffraction grating up to their eyes. It may be necessary to rotate the diffraction grating in order to see the emission lines. Be patient! 3. Record the colors of the light's emission lines in column three of the Data Table. 4. Draw the emission spectrum observed (THEY CAN USE THE COLORED PENCILS) Measure and draw the wavelength of any line spectra that appear on Light
Observed Color of
source
light
Emission the blank spectrum on your data sheet. Sketch the range of any colors observed using the colored pencils, and note the regions where Color
Lines
the colors are most bright and most dim.
Fluorescent
light
Lamp 1
Lamp 2
Lamp 3
Lamp 4
GEMS ‐‐ Spectroscopy and Space Analysis: Each lamp contains one of the following four elements, He, Hg, O, Ne. Go the website http://chemistry.bd.psu.edu/jircitano/periodic4.html and click on the elements helium, mercury, oxygen, and neon to see its spectrum. Compare your spectrum to the ones at the website. Which lamp is which element? Record below. Light source
Element
Lamp 1
Lamp 2
Lamp 3
Lamp 4
Discussion: 1. When the spectroscope was used to view the lamp, explain why different colorful emission lines were observed for the elements. 2. Colorful light emissions are applicable to everyday life. Where else have you observed colorful light emissions? Are these light emission applications related? Explain. 3. Helium was discovered in the Sun's corona during the eclipse of 1868. In 1888, traces of helium were isolated here on Earth. How could scientists determine that this was the same gas that had been identified on the Sun?