4Wave-7

Outcomes

• Pupils can identify the sections of the electromagnetic spectrum.
• Pupils can identify the uses and dangers of sections of the electromagnetic spectrum.

Specification References

• 3.10 understand that light is part of a continuous electromagnetic spectrum which includes radio, microwave, infrared, visible, ultraviolet, x-ray and gamma ray radiations and that all these waves travel at the same speed in free space
• 3.11 recall the order of the electromagnetic spectrum in decreasing wavelength and increasing frequency, including the colours of the visible spectrum
• 3.12 recall some of the uses of electromagnetic radiations:
• 3.13 recall the detrimental effects of excessive exposure of the human body to electromagnetic waves:

Starter

• Show pupils EM spectrum circus.

Main Body of Lesson

• Assign each group of pupils two sections of the EM spectrum, pupils should find the uses of one section and the dangers of another (AGR has hand-out cards for pupils).
• Pupils present uses and dangers to the class.
• During talks pupils should make rough notes, which will then be made into neat notes for homework.
• Alternatively go through the following with the group:

Uses

• Radio - communication
• Microwave - communication, energy transfer (e.g. microwave oven, solar satellite)
• Infrared - thermal energy transfer, night vision
• Visible
• Ultraviolet - sterilisation, tanning,
• X-ray - medical (diagnosis), x-ray diffraction (crystallography)
• Gamma ray - sterilisation, medical (treatment)

Dangers

• Radio - negligible hazard (possibly KISS FM)
• Microwave - negligible hazard, internal heating
• Infrared - surface heating
• Visible
• Ultraviolet - blindness, sunburn
• X-ray - blindness, cancers (mutation)
• Gamma ray - blindness, cancers (mutation)

Have pupils produce a mnemonic to help remember the order of the EM spectrum. The odder the better. E.g. red monkeys in Vietnam use xylophones greatly.

Plenary

• Use Jodrell Bank's Chromoscope to explore the sky in different parts of the spectrum.

Homework

• Using rough notes created in class, combined with textbook/internet, pupils create neat notes on uses/dangers of each section of the EM spectrum.

Additional Information

Textbook References

• Pople 7.11 pp. 160-163

Safety/Hazards

Exposure to intense UV Radioactive source handling