Unlike sound or earthquakes, light waves can transfer energy anywhere, whether there is a medium to carry it or not. Light is all around you with wavelengths bigger than mountains and smaller than atoms. But your eyes can see only a tiny part of those light wave--the visible light. So in other words, even when it's dark there are other light waves you can't see that are going around you, bouncing off of you and even going through you.
Watch this video to find out more about light waves and their properties. Then, answer the question in the Take Notes box, below. You may read the transcript to the video, and watch the segment, as many times as you like.
| Keyboard Shortcut | Action |
|---|---|
| Space | Pause/Play video playback |
| Enter | Pause/Play video playback |
| m | Mute/Unmute video volume |
| Up and Down arrows | Increase and decrease volume by 10% |
| Right and Left arrows | Seek forward or backward by 5 seconds |
| 0-9 | Fast seek to x% of the video. |
| f | Enter or exit fullscreen. (Note: To exit fullscreen in flash press the Esc key. |
| c | Press c to toggle captions on or off |
Waves transfer energy. Mechanical waves, like sound, earthquakes, or waves on a pond, transfer energy by vibrating actual particles.
But there is another type of wave called an "electromagnetic wave," and just like a ripple on a pond, electromagnetic waves have wavelengths, frequency, and amplitude that can be measured. But instead of surveying them, we can see some of them. Electromagnetic waves are light waves.
And the unique feature of light waves is that they can transfer energy even when there are no particles to be found. Put a light bulb, a firefly or say, the sun, up in space and that light energy will travel even though there are no actual particles. Once those electromagnetic waves get to our little planet, they react with the matter here on earth to continue that energy transfer.
And thank goodness they do, because we here on Earth rely an awful lot on that light energy from the sun.
In this lesson you'll learn some basic information about electromagnetic or light waves. You'll watch a short video and then three animations that explain the nature and characteristics of light, as well as how light interacts with objects. After taking notes and online quizzes, you'll have a chance to review and organize what you've learned. Then you will produce your own project in which you'll define and describe light waves.
Answer the following two questions in the note box, below. (Click SAVE when you have finished. To see your saved or submitted work again, click MY WORK at the top of the page.)
1) What are electromagnetic waves?
2) What are the three characteristics of electromagnetic waves that can be measured?