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41 Waves and Technology
ENGAGE: Communicating with waves 1. You may be aware of the various types of electromagnetic waves used in communication technology. In groups discuss what you know about how each of the pieces of technology transmits or receives information: (a) AM radio:
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(b) FM radio:
(c) Cellular phone:
(d) TV satellite:
(e) Bluetooth emitter:
(f) WIFI emitter:
EXPLORE: Encoding and decoding information
`` We have seen that waves transfer energy but do not transfer matter. Using technology the basic features of waves can be manipulated so that they can also rapidly convey vast amounts of information over very large distances.
`` Waves convey information in two general ways:
• Information about a medium can be obtained simply by the way a wave is affected as it travels through that medium, e.g. seismic waves, MRIs and x-rays.
• Waves can be used as a “vehicle” for transmitting information that we want to send from one place to another, e.g. radio waves. A
first be able to encode our information into waves and then decode the waves once it has reached the receiver.
`` First let us look at how information can be encoded. One
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of the simplest ways is something like Morse code were information is encoded as simple dots and dashes.
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2. Think of a short sentence. Write it out in Morse code below and see if a classmate can decode it:
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`` For waves to transmit and receive information we must
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Morse code
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