Electromagnetic energy is the energy that comes from electromagnetic radiation. This radiation is composed of waves, including radio waves, visible light, and x-rays. Electromagnetic energy moves at the speed of light in a way that is similar to both waves and particles. (In this lesson we will be discussing the wave model of electromagnetic energy.) Electromagnetic radiation creates both electric and magnetic fields. Much of the electromagnetic energy on earth originates from the sun.

The image below shows the parts of a wave. The peaks or crests are at the highest points of the wave. The troughs are the lowest points of the wave. The wavelength is the distance between two corresponding points on adjacent waves.

Source: Cosmetic Toiletry and Perfumery Association, Parts of a wave, Faces of Science

1. Go to the following website.
2. Under Parts of a wave, click on the different links

• Picture of a Wave
• Crest and Trough
• Amplitude
• Wavelength
• Frequency
3. Pay close attention to the sections on wavelength and frequency.
4. You can even manipulate the frequency on a wave to see the differences.

You will need to remember these parts in order to understand the electromagnetic spectrum. Because, the electromagnetic spectrum is just a continuum of all electromagnetic waves arranged according to wavelength and frequency.

If you are still having trouble with wavelength and frequency try this simulation. Click on the link to access the Boat Simulation. Manipulate the frequency and see how that affects the boat and the graph.

Now, let's move on to the electromagnetic spectrum.