Goal: To observe several spectra.
Materials (available from educational or science supply stores)
- Diffraction grating
- Colored celophane
- Paper or plastic tube
- Follow the instructions at the Patterns in Nature site for the making your own spectrometer in their Prisms and the Spectrum Lab, or use the spectromscope tube in your AP lab kit. You can open the tube and create a scale inside.
- View at least four of the following
- Household incandescent light bulb
- Fluorescent bulb
- Yellow (sulfur) street lights
- Blue/white (mercury) street light
- Sunlight reflected off a sull white surface (e.g., a cloth sheet or piece of paper)
- "Neon" shop signs of different colors [Red ones are likely to actually be neon; other colors use other gases)
- Use the wavelength scale to estimate the position of the emission spectrum lines.
- Use the pattern of lines to identify the type of material from which they come for each of your observations.
- Describe your materials, equipment, an dprocedures in sufficient detail that your fellow students could repeat your experiment.
- Report your data. Be sure to indicate the amount of error in your measurements. For example, if you can only measure a wavelength to within 10nm, your values should read "400nm ± 10", or 10/400 = 2.5%.
- Present your data in an organized form, preferably in a table, in such a way it is easy to compare results as you repeate trials or vary a specific contributing factor.
- Show a sample calculation, if you have calculated values.
- If you did a series of experiments, varying something by increasing or decreasing a factor, try to plot your data (y-axis) as a function of the factor (x-axis).
- You may use a spreadsheet to calculate your information and create your table.
- Summarize your results.
- Draw conclusions about what is happening.
- Suggest at least one way to improve your experiment.
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