Science Vault - Year 11 HSC Physics

8.2 - The World Communicates

Content Links

wave model




electromagnetic spectrum




Other Useful Links

board of studies

csu hsc online

uniserve chemistry links

eric weintein's world of physics

Contextual Outline

Humans are social animals and have successfully communicated through the spoken word, and then, as the use of written codes developed, through increasingly sophisticated graphic symbols. The use of a hard copy medium to transfer information in coded form meant that communication was able to cross greater distances with improved accuracy of information transfer. A messenger was required to carry the information in hard copy form and this carrier could have been a vehicle or person. There was, however, still a time limit and several days were needed to get hard copy information from one side of the world to the other.

The discovery of electricity and then the electromagnetic spectrum has led to the rapid increase in the number of communication devices throughout the twentieth century. The carrier of the information is no longer a vehicle or person — rather, an increasing range of energy waves is used to transfer the message. The delay in relaying signals around the world is determined only by the speed of the wave, and the speed and efficiency of the coding and decoding devices at the departure and arrival points of the message. The time between sending and receiving messages through telecommunications networks is measured in fractions of a second allowing almost instantaneous delivery of messages, in spoken and coded forms, around the world.

This module increases students’ understanding of the nature, practice, application and uses of physics and current issues, research and developments in physics.

Assumed Knowledge

Domain: knowledge and understanding:

Refer to the Science Stages 4–5 Syllabus for the following:

5.6.1a Identify waves as carriers of energy.

5.6.1b Qualitatively describe features of waves including frequency, wavelength and speed.

5.6.1c Give examples of different types of radiation that make up the electromagnetic spectrum and identify some of their uses.

5.6.4a Distinguish between the absorption, reflection, refraction and scattering of light and identify everyday situations where each occurs.

5.9.1b Identify that some types of electromagnetic radiation are used to provide information about the universe.

5.12c Describe some everyday uses and effects of electromagnetic radiation, including applications in communication technology.

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