The Franklin Institute's Resources for Science Learning x
Home (Main Navigation - Resources for Science Learning @ The Franklin Institute)For Learners (Main Navigation - Resources for Science Learning @ The Franklin Institute)For Educators (Main Navigation - Resources for Science Learning @ The Franklin Institute)Leadership (Main Navigation - Resources for Science Learning @ The Franklin Institute)Partnership (Main Navigation - Resources for Science Learning @ The Franklin Institute)About Us (Main Navigation - Resources for Science Learning @ The Franklin Institute)

Shhh!

L i s t e n   T o   T h e   A i r

 
A RADAR view of Texas

If you're in a room with a window, go open the window. Then come back. If you're not in a room with a window, just wait quietly.

Finished? Good. You just let all of the radio waves into the room.

Radio waves are constantly traveling through the air in your community. They're invisible, like light waves. Together, radio and light waves are part of the spectrum of electromagnetic energy. The radio waves are the longest in the spectrum, making them easiest to generate and transmit over long distances. This physical property makes radio waves an ideal means of communication.

Do you have a radio? You know, an old-fashioned AM/FM radio? Inside your radio is a "receiver" which receives and translates the communication signals carried on the radio waves that are traveling through the air in your community. Each "radio station" in your community transmits radio waves at their own unique "frequency." That way, you can tune in and receive their radio waves instantly. Or, what seems instant to our ears. Radio waves travel at the "speed of light," 186,282 miles per second. So, when your team's star hitter swings the bat and sends the baseball soaring out of the stadium, the radio announcer's excited cry reaches your radio just a tiny little fragment of a second later.

The air in your community and in your room is an ideal "transmitter" of the radio waves. The air allows the radio waves to travel comfortably through. Many materials, however, do not allow the radio waves to travel through; rather they "reflect" the radio waves, causing them to bounce back. The metal of an airplane's wing, the rock of a mountain, and the water in a storm cloud are all reflective materials. When radio waves hit them, the waves bounce back.

These properties of materials and of radio waves made RADAR possible.

 
GO: