Mrs. Hughes
Date: ________
EM Spectrum & Waves
Name: __________________
Core #: ________
Electromagnetic Spectrum Waves Powerpoint Slides:
2. Electromagnetic Radiation (energy)  comes from the ______________________.
* Energy from the sun (152 million km away) reaches earth in _________minutes.
Travelling at the speed of light 300,000 km per second
3. Electromagnetic Spectrum Waves:
long wavelengths = _______________ waves
short wavelengths = ______________ waves
4. The sun's energy reaches the Earth in _____________________________ waves
(ie. x-rays, light rays, gamma rays) – S waves
5. Two types of waves:
a) Compressional waves - such as ________________waves; require a medium to
transfer energy.
b) Transverse waves - such as ____________________ waves - can transfer energy in a
vacuum, without a medium.
6. Wave Characteristics: Label- Crest, Trough, Amplitude, wavelength, & Rest position
(or equilibrium poition)
7. ______________________= the number of wave crests that pass a point during one
second. Measured in _____________ (Hz =cycles per second).
* Note: as wavelength increases, frequency ________________________.
8. ______________________= amount of energy transferred (hint: dimmer switch).
The larger the amplitude the (higher or lower) the energy.
9. Electromagnetic Spectrum: Wonders?
10. Radio waves = Wavelength longer than 30cm (AM radio appx. 1km)
Uses: _____________________________________________________
* Your radio captures radio waves emitted by radio stations (stations accelerate electrons
in a circuit with an antenna). Electrons wiggling back & forth create an EM wave
* So many senders & receivers international regulations on frequencies
* In space, radio waves are created by electrons accelerating away from supernova
explosions, by some galaxies, by clouds of gas where stars are forming, and by rotating
collapsed dead stars (neutron stars). Astronomers used radio waves from space to detect
the presence of a black hole.
11. Microwaves = 1mm – 30cm
Uses:
*______________________ – cause water molecules to vibrate enthusiastically (heat)
*_______________________- Wifi & Bluetooth
* by astronomers to learn about the structure of nearby galaxies
12. Infared Radiation = 1 millionth meter – 0.1 mm (point of a pin)
* Slightly less energy than visible light
* Produced by the vibration of atoms within molecules – we perceive this as heat
Uses:
* _____________Photographs – houses; diseased areas on the surface of the human body
* __________________________________ for TV
13. Visible Light = size of a bacterium
Lowest energy visible light we see = _____________________(750nm)
Highest energy visible light we see = _____________________(450nm)
14. Ultraviolet = size of a virus (10nm)
* Slightly more energy and shorter wavelength than your eyes can detect
* Some insects can detect near UV light
Uses: * _________________________: long exposure = damage to skin & eyes
* _________________________: Counterfeit money & black light paint
15. X-Rays = 10nm-0.01nm (size of a water molecule)
* Discovered in 1895 & put to use in ____________________imaging
* More energetic & shorter wavelength than UV so they pass right through matter that
appears opaque to our eyes.
* Used to measure thickness in _________________________.
16. Gamma Rays = 0.01nm – 0.0001nm (smaller than an atom)
* Short wavelengths & more energy
* Blocked only by thick heavy metals (lead & concrete)
* Can damage living tissue & DNA
* Sometimes used to kill cancer cells & irradiate medical equipment & food to destroy
bacteria
* On earth, most come from nuclear reactions & decay of radioactive materials
* Astronomers use these rays to study unusual events in distant galaxies (pulsars, quasars,
hypernovae)
17. Foot: can only be viewed in X-ray, UV, Visible, and Infared
a) Observations?
Infared:
Visible:
Ultraviolet (UV):
X-ray:
18. Moon:
a) Observations?
Radio:
Microwave;
Infared:
Visible:
Ultraviolet (UV):
X-ray:
Gamma ray:
20. Let’s take a closer look at the Electromagnetic Spectrum
1. What do you notice?
2. What uses Infrared radiation?
3. What is UV protection on Sunscreen?
4. What type of radiation has the longest wavelength and lowest energy?
5. What type of radiation has the shortest wavelength and the highest energy?
6. What types of radiation have higher energy than visible light? Which have lower
energy than visible light?