Level 8 physics: Telecommunications 3
As well as the overarching ideas and focus statements that underpin this particular programme, this section gives a set of example activities that are linked to various parts of the nature of science strand of the curriculum, showing how this strand can be embedded into the teaching programme.
Focus statements
- Simple electrical devices (capacitor, inductor, etc.) form the basis of alternating current (AC) electrical circuits. These circuits can be arranged in different ways to perform many different functions.
- Alternating current can be analysed using the concept of simple harmonic motion (SHM).
- Alternating current circuits can be analysed as if they were direct current (DC) circuits by using root mean square (RMS) voltages and currents.
- Capacitors and inductors both store energy.
- The relationship between reactance and resistance and the relationships between reactance and frequency for an inductor and a capacitor.
- There are phase differences between components of an AC circuit such as inductors, capacitors, and resistors.
- A phase difference between the voltages and reactances of capacitors, resistors and inductors can result in resonance. The LCR circuit is an example of resonance.
- A variable capacitor/inductor device can be used to adjust the resonant frequency.
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Possible activities based on the NoS strand
Communicating in science, participating and contributing
- Since the beginning of telecommunications the frequencies used to transmit signals have increased from Hz to KHz to MHz. Discuss whether this increase can continue. If not, what would be the limits of any increase? Discuss any social implications of increasing frequencies.
Understanding in science, participating and contributing
- Currently there is a debate about the positive and negative effects of cellphone use on people’s health. Research both sides of the argument and use this information to discuss how it is possible for scientists reach different conclusions on this issue.
Discussion activities
- Discuss how and why electricity is transmitted over long distances, using AC not DC.
- Discuss how large industrial factories work with electrical supply companies to ensure maximum efficiency.
- Discuss why Tesla’s invention of an AC motor and the transformer were influential in the decision to accept AC as the best choice for the transmission of electricity.
Investigative experiments
- Find the relationship between RMS voltages/currents and their peak values.
- Find the relationships between reactances and frequency.
- Construct (and disassemble) a functional radio receiver device.
- Construct (and disassemble) a functional radio broadcaster device.
- Construct an operational and adjustable LCR circuit.
Community exercise
- Visit and report on an operational telecommunications station.
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Possible assessments
Learning could be assessed using a variety of standards – for example:
- AS91522 Physics 3.2: Demonstrate understanding of the application of physics to a selected context (building a device) (3 credits, internal)
- AS91523 Physics 3.3: Demonstrate understanding of wave systems (4 credits, external)
- AS91526 Physics 3.6: Demonstrate understanding of electrical systems (6 credits, external)
- AS91527 Physics 3.7: Use physics knowledge to develop an informed response to a socio-scientific issue (3 credits, internal)
Last updated May 6, 2013
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