2. Electromagnetic Waves

3. Electromagnetic energy is created by objects in outer space and by humans.

4. Wave Properties All electromagnetic waves travel at the speed of light (3.00 x 10 8 meters/sec) Some electromagnetic waves are invisible while others are visible.

5. Waves Each wave consists of a crest and a trough.

6. Amplitude The amplitude is the height measured from the midpoint to the top of the crest.

7. Wavelength λ Wavelength is measured as a complete wave cycle.

8. Frequency Frequency is the number of waves that pass a reference point in a given time. = λ/s

9. The unit for frequency, (cycles per second) is hertz. The radio station Has a frequency of 95 megahertz. 95 X 10 6 hertz (Hz) is their broadcasting frequency.

10. Frequency and Wavelength As frequency increases wavelength decreases. F = 1/w

11. Continuous Spectrum Wavelength increases from left to right on this spectrum. Visible light is measured in nanometers (nm); 1 billionth of a meter (10 -9 )

12. What does this have to do with atoms? When atoms get excited, 1) electrons jump up to higher energy levels momentarily, then 2)fall back to their lower energy level. When they fall, they lose energy and 3)the lost energy is released in the form of visible waves we see as color.

13. Different Element Emission Colors Each element has its own spectrum depending on its electron configuration. Electrons that fall more energy levels tend to emit violet wavelengths. Electrons that only fall one or two levels tend to emit red wavelengths.

14. Wave Effects Waves can undergo reflection, refraction, diffraction, and polarization.

15. Wave Effect Examples Reflection means they reflect or bounce off something else. Refraction means they bend as they pass through something else. Diffraction and polarization occur when the waves are separated into different wavelengths.

16. Element Spectra http://jersey.uoregon.edu/vlab/elements/Elements.htmlhttp://jersey.uoregon.edu/vlab/elements/Elements.html Each element has its own emission spectrum, based on its electrons. When electrons are excited they 1) jump to higher E levels, 2) then fall back down, 3) releasing wave energy in specific wavelengths we see as color.

17. Waves: Hot or Not?

18. Definitely HOT!