Now that we understand what the radio wave is doing in space let us apply it to normal society.

We used sound waves in the demonstration because those are familiar to everyone. When we graph radio waves, they are no different than when we graph sound waves; they look the same. The reason we need radios to listen to broadcast stations is because the human ear is only capable of registering frequencies in the "audio" portion. Our eyes are only capable of seeing frequencies in the "visual" portion. This is how infra red works. With technology we are able to develop cameras that receive frequencies in the "heat" portion. Heat waves travel just like any other energy wave. This is why an infra red camera can see bad guys at night because it is "tuned" to receive the frequency of heat that leaves our bodies.

Below is the top portion of the electromagnetic spectrum. This image was originally tilted 90 degrees. I pointed it so that the sign wave moves down just so you could read it better. You will notice that as the wave continues the amplitude (strength) never changes, only the frequency. As the frequency gets lower and lower you will see that the wavelength on the left gets bigger. You should also notice some terms on the right that you know. As we start at the top, Gamma Rays, and move down and get lower in frequency you will see that we get to X-Rays. X-rays are used in the medical field. Gamma rays go through even bone so they are not useful. Light waves don't go through skin so they would not be useful either. X-rays are used because they can go through skin but not bone.


As you get lower and lower in frequency we go through visible light and we get to infra red which we discussed earlier. They are just below the visible light spectrum which is why they can be seen at night. When one compares violet light with red light one might simply say that the only difference between the two is the frequency of the energy wave. The human brain interprets those energy waves as colors. (The term Ultra Violet Light literally means "Light above violet; the term infra-red light literally means "light below red")

We continue to drop in frequency and we get to "microwaves" which are used in "microwave ovens". These are simply radio waves at the top end of the "Radio Frequency Spectrum". All a microwave oven does is point a high-power radio transmitter at whatever food is placed inside. The radio waves interact with the water molecules and heat up the food.

As we continue to drop we get to standard radio waves. One of the items on the list is "10 meters" which just happens to be a ham radio "band".

The only thing that separates X-Rays, sound waves, light rays, RADAR waves et cetera is the frequency of the sine wave.


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