Year 9 Science Exam Prep — Episode 7: Waves Extended — The Electromagnetic Spectrum

This episode is a deep-dive revision lecture on the electromagnetic spectrum, built for Year 9 students preparing for their science exam.

What this episode covers

What electromagnetic waves are and how they travel
The seven types of EM radiation in order of frequency: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays
Properties, uses, and hazards of each type
The difference between ionising and non-ionising radiation
Medical imaging techniques that use EM radiation (thermal imaging, endoscopy, X-ray, CT, gamma scanning, MRI)
EM waves in communication (broadcasting, satellite, mobile networks, fibre optics, radar)
Four worked exam questions with model answers
Summary of key facts and exam tips for the whole topic

Chapters are available in your podcast player's chapter view.

Learn the order of the spectrum: radio — microwave — infrared — visible — ultraviolet — X-ray — gamma (lowest to highest frequency).
Non-ionising: radio, microwave, infrared, visible. Ionising: high-frequency UV, X-rays, gamma rays.
Always state which type of EM radiation a medical technique uses — this is a very common exam question.
When comparing two types of EM radiation, refer to frequency, wavelength, and ionising ability.
MRI uses radio waves (non-ionising); CT uses X-rays (ionising) — know the difference.