1. Spectra

2. Visible light is one small portion of the electromagnetic spectrum
When light is refracted (bent), the light is split into its individual wavelengths
Each wavelength appears as a different color
The entire range of colors makes up a spectrum
We can refract light with an instrument called a spectroscope

3. Types Of Spectra

4. 1. Continuous
Formation- when a solid, liquid, or high pressure gas is heated to a high temperature, it emits all wavelengths Appearance- a full rainbow
Image from
INCANDESCENT BULB

5. 2. Bright-line emission
Formation- when a low pressure or low density gas is heated, the electrons get excited and jump energy levels. Energy is emitted at specific wavelengths. Each gas has its own distinct pattern
Appearance- a couple thin lines of color

6. 3. Continuous with bright lines
Formation--Common in fluorescent bulbs Appearance-a full rainbow in the background with a few especially bright lines
FLOURESCENT BULB

7. 4. Absorption/ Continuous with Dark lines
Formation-caused when cooler atoms are between the light source and the observer and remove (absorb) certain wavelengths of light. Common in stars
Modified from
STAR
FILTERED LIGHT
Light source
Cool gas
You
Appearance-as a chunk of a rainbow or a rainbow with black lines through it

8. IMPORTANCE
Scientists can determine the composition of stars by matching the dark line pattern in the star’s spectra with the bright line emission patterns of known gasses