A radio will receive electromagnetic waves sent out by a transmitter. These waves are transmitted into sound waves through a radio. The waves sent through the air are different sound waves. These sound waves follow the sine/cosine wave pattern. Each different radio uses a different sine wave at a different frequency. That is how they are separated. Different amplitudes and frequencies create different sounds., such as tuning forks work. The larger the tuning fork, the greater the amplitude (louder the sound), and the smaller frequency (lower pitch). Radio's work in the same way by sending out different sized waves into the air to be received and interpreted by the receiving radio. An AM radio recognizes a difference in the amplitude of the waves. AM radio's typically will not play very much music and well be more talk and information. An FM radio recognizes the varying frequency of the waves. This allows music to be transmitted through space and recieved, then turned into what we hear.
Parts of the radio
The Mechanism- Is the part of the radio that creates the energy and allows the radio to turn waves into sound.
The Transmitter- Produces the Alternating current and makes the energy to produce a signal
Transmitting Antenna- Takes the signal and sends it out into space
Receiving Antenna- intercepts the electromagnetic waves
Radio stations use a radio tower to send signals out to everyone within reach. In some cases, these signals are sent for miles, and each one has a different frequency.The frequency is recieved by a reciever or a stereo in this case. Each station has a set frequency to the dial. So, when u set your dial to 106.7, you are setting your stereo to only listen to that type of frequency sound waves.
How to build a Fox-Hole Radio
First we wrapped a 5 inch PVC pipe with copper wire 120 times, making sure there is a good amount left on one end. Then we placed paper clips so we had one to hook up a ground wire, speakers, and antenna. Then we drilled the PVC pipe to the block of wood. We drilled in a razor blade that was fired. We connected a pencil to a safety pin so that the lead of the pencil was touching the safety pin. We placed the lead of the pencil on the razor blade on the part that was fired. We used copper wire to connect the ground wire, to the speakers, then to the paper clip that touches the copper wire on the PVC pipe. We took more copper wire and connected the other head speaker paperclip to the safety pin with the pencil on the end. Use the extra wire from the PVC pipe and connect it to the antenna paper clip then to the razor blade. Make sure you sand all the connections to get the coating off it will produce better sound.
http://news.softpedia.com/news/How-Does-the-Radio-Work-75702.shtml
http://electronics.howstuffworks.com/radio.htm
http://www.buzzle.com/articles/how-does-a-radio-work.html
http://www.ehow.com/how-does_4899946_radio-stations-work.html
Interesting that we can set our dial to a certain station, such as 106.7, and there are mechanisms that work to only stream into our ears that frequency. Isn't that amazing how so many waves are around us, and a small group of things thrown together can select a certain type of wave and allow us to hear it...
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