Year 11 Physics Syllabus Dot Points - the World Communicates

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8.2 The World Communicates
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.

1. The wave model can be used to explain how current technologies transfer information 1.1 - describe the energy transformations required in one of the following: • mobile telephone • fax/modem • radio and television • Mobile phones have a built-in microphone that changes sound waves into electrical signals. These signals are digitised, and transmitted as radio waves to a base station. This base station consists of a system of antennae on top of a tower, and each base station accepts and can transmit radio signals from three adjacent hexagonal-shaped areas called cells. Each base station is connected to a switching centre by a cable network that carries the signal as electrical impulses. These impulses have been produced by radio-wave energy interacting with the aerial. Each switching centre is connected to other switching centres and base stations. There are three main possible paths for the signal to take: a telephone call between a mobile and a distant fixed telephone (conversion to light), a telephone call between a mobile and a fixed telephone close to the aerial (electrical impulses), or if the telephone call is between one mobile to another (converted to electrical then to radio waves). 1.2 - describe waves as a transfer of energy disturbance that may occur in one, two or three dimensions, depending on the nature of the wave and the medium • Depending upon the type of wave and the medium in which they are traveling, waves may be traveling in one, two or three dimensions. o One dimensional wave – an example of a a 1D wave is a transverse or longitudinal wave in a slinky or a transverse wave traveling along a rope. It is a 1D wave beause the wave is confined to the rope or the slinky. o Two Dimensional waves – An example of a 2D wave is a transverse wave that travels outwards from the medium like when a stone is thrown into the water and the waves produced travel outwards from that medium. o Three dimensional waves – An example is sound waves. Consider a point source of sound- it results in a sound wave that immediately travels away from the source in three dimensions with a spherical wavefront. 1.3 - identify that mechanical waves require a medium for propagation while electromagnetic waves do not Mechanical waves, such as sound waves, water waves and earthquake waves need a medium (a substance) to travel through, they cannot move from one point to another if there is...
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