How can spectra tell us what things are made of?
Stars and planets are too far away for a human to touch, yet we know what they are made of. Spectra make this possible! Let’s investigate how.The Sun's Composition
The Sun’s absorption lines tell us what elements are present in its gas. For example, we know that hydrogen is the most common element in a star.
Spectrum Tool. Compare the spectra to identify what the Sun is made of.
- Under Source 2, use the dropdown menu to select the Hydrogen Emission spectrum.
- Identify three distinct wavelengths where absorption lines appear in the Sun’s spectrum and emission lines appear in the hydrogen spectrum. Use information about these lines to complete the Table in Question 1 in your Notebook.
- Under Source 2, use the dropdown menu to compare other atomic spectra with the Sun's spectrum. Identify one other element that is present in the Sun based on the comparison spectra. Use the information to answer Question 2 in your Notebook.
Note: A particular element like hydrogen can either absorb or emit light. Either way, the lines will occur at the same specific set of wavelengths and can be used as the “fingerprint” for that element.
Spectrum Notebook. Answer these questions in your Notebook.
- Complete the Hydrogen in the Sun table. For each of the lines that had a match between the Sun's spectrum and the hydrogen spectrum: write the wavelength of the line, describe how it appears in the Sun's spectrum, and how it appears in the hydrogen spectrum.
- Identify one other element that is present in the Sun based on the absorption and emission spectra.
Source 1:
Stars — Sun
Brightness 
Wavelength (microns) Source 2:
Brightness Wavelength (microns)