1. Continuous, Emission, and Absorption
Three Types of Spectra
Continuous, Emission, and Absorption

2. Continuous, Emission and Absorption.
There are three different types of spectra scientists can measure:
Continuous, Emission and Absorption.

3. Continuous Spectra, and Blackbodies
Blackbodies - and near blackbodies, like stars - emit waves of EM radiation whose frequencies change gradually.

4. They emit a continuous spectrum.
The intensity of specific wavelengths may vary, but there are no gaps in the spectrum bar.

5. Emission Spectra
A hot gas will only give off the specific EM energy ( i.e wavelenths) that match its molecules.

6. These spectra will appear as bright lines at specific wavelengths with gaps in between… an Emission Spectrum

7. The pattern of bright lines from a hot, glowing gas in the emission spectrum tells us what elements the gas is made of.

8. The Photo-Electric Effect
A photon is created when an electron jumps from a higher to a lower energy orbit.
The wavelength of the photon depends on the energy difference between the orbits.

9. So the unique orbit pattern of each element or compound creates certain specific wavelengths of light.
An electron can also absorb only those wavelength’s light.

10. Absorption Spectra
When light is reflected off of or passes through a cool gas it is absorbed, but only those wavelengths that the specific gas can absorb.

11. Dark lines will appear in spectra of such light
Dark lines will appear in spectra of such light. This is called an absorption spectrum.
The pattern of dark lines in the absorption spectrum tells us what the cool gas is made of.