1. Light and the Electromagnetic Spectrum

2. Review
Frequency
Wavelength
Energy

3. Applications
Radio: Your radio captures radio waves emitted by radio stations, bringing your favorite tunes. Radio waves are also emitted by stars and gases in space.
Microwave: Microwave radiation will cook your popcorn in just a few minutes, but is also used by astronomers to learn about the structure of nearby galaxies.
Infrared: Night vision goggles pick up the infrared light emitted by our skin and objects with heat. In space, infrared light helps us map the dust between stars.
Visible: Our eyes detect visible light. Fireflies, light bulbs, and stars all emit visible light.
Ultraviolet: Ultraviolet radiation is emitted by the Sun and are the reason skin tans and burns. "Hot" objects in space emit UV radiation as well.
X-ray: A dentist uses X-rays to image your teeth, and airport security uses them to see through your bag. Hot gases in the Universe also emit X-rays.
Gamma ray: Doctors use gamma-ray imaging to see inside your body. The biggest gamma-ray generator of all is the Universe.

4. Drawing Waves

5. These kind! ROYGB(I?)V Review your units!
Wavelength (lambda): meters (m)
Frequency (nu): Hertz (Hz) or oscillations per second

6. How fast does light or photons travel?
Faster than anything else on earth…
Speed of light (c) = 3.00 x 108 meters per second (m/s)
Use this number for your calculations.
670,616,629 miles per hour
186,282 miles per second
983,571,056 feet per second

7. How is the speed of light, wavelength, and frequency related?
Wavelength and Frequency are INVERSELY PROPORTIONAL
Calculate the wavelength of yellow light emitted by the sodium lamp shown above if the frequency of radiation is 5.10 x 1014 Hz (s-1).

8. One more for practice:
What is the frequency of radiation with a wavelength of 5.00 x 10-8 m? In what region of the electromagnetic spectrum is this radiation?

9. We can also relate energy to frequency:
h= planck’s constant= x joules·second (J·s)
E = energy (joules) (J)
v= frequency = oscillations per second (osc./s)

10. Example:
What is the energy of a photon of microwave radiation with a frequency of 3.20 x 1011 s-1 (or Hz) ?

11. Atomic Spectra
When atoms absorb energy, electrons move into higher energy levels. These electrons then lose energy by emitting light when they return to lower energy levels.
This happens by passing an electric current through a gas.

12. Examples:
2.0 x 10-7 m to 8.0 x 10-7 m.
They are giving you nanometers.
They just converted the numbers .
Each element has a unique emission spectrum. Like a fingerprint.

13. Applications
Because each element has a unique emission spectrum, we can determine the composition of the universe…
The atomic spectra of starts for example.
They are hot glowing bodies of gases!

14. Applications: Spectroscopy/ Quantitative Analysis
Spectroscopist: finds the chemical contents of unknown materials in chemical research.
Chemical research
Police Investigations: Forensics
Studies of the Universe
Environmental Scientist
ETC.

15. Spectrometer

16. What are some research ideas?
You decide…
How much of THAT is in that?

17. Looking forward Unit 1 Test : Notes #1-3 and Article Materials
Thursday August 28th
Lab Report 1: Spectroscopy Inquiry
We will begin process on September 2. Due date to be announced.