# Notes #3

``` Frequency
 Wavelength
 Energy

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. &quot;Hot&quot;
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.
ROYGB(I?)V
Wavelength (lambda):
Frequency (nu):
meters (m)
Hertz (Hz) or oscillations per second
 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
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).
 What is the frequency of radiation with a wavelength
of 5.00 x 10-8 m? In what region of the electromagnetic
 h= planck’s constant= 6.626 x 10-34 joules&middot;second (J&middot;s)
 E = energy (joules) (J)
 v= frequency = oscillations per second (osc./s)
What is the energy of a photon of
microwave radiation with a frequency of
3.20 x 1011 s-1 (or Hz) ?
 When atoms absorb energy, electrons move into higher
energy levels. These electrons then lose energy by emitting
This happens by passing an electric current through a gas.
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.
 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!
 Spectroscopist: finds the chemical contents of
unknown materials in chemical research.
 Chemical research
 Police Investigations: Forensics
 Studies of the Universe
 Environmental Scientist
 ETC.
 You decide…
 How much of THAT is in that?
 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.
```