Waves
What has the cat to do with waves?
We all know what water waves are. Physicists also say that light is a wave, and even matter sometimes behave like a wave. This has some consequences we should look at. Below you can see the wavelab. The slider controls the wavelength. You can place a probe (the middle of the cross) with the mouse and see the wave at this point above. You can switch between two light sources or use them together.
The Wavelab
(Java applet. You need a fast computer to get the right feeling)
Click here for a bigger (even slower) version
New: get the wavelab on your mobile phone. Visit Handylearn Projects for more information.
If you use both light sources together, you get something which is called interference. Please notice that some spots of the picture are not changing: there are some green lines that stay green. If you place the probe in this spot you see the amplitude of the wave is very low or is even disappering. But because a wave only exist if it changes, in this spots the wave disappears! So, sometimes light and light leads to darkness!
But why don't we see this in our normal live? When I switch on two lights in my room, there are no spots which suddenly gets dark when the second light gets on. And why didn't I get hypnotized from all this light waves if they look like in our lab? So is this all pseudo-scientific nonsense?
Actually, there are two reasons we can not see this normally: first the light waves are very short, about one thousand of a millimeter. And secondly, normal light from the sun or a light bulb is a chaotic mixture of many different wavelength and phases. But we can construct experiments to show that sometimes light and light is darkness.
What are these Experiments? And will the cat get hypnotysed ?
soon available on this web site
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