Year 9 Science · Unit 4 · Lesson 8

The Electromagnetic Spectrum

Challenge Worksheet

Name

Date

Class

Learning Goals

Classify applications and hazards of EM radiation across all seven spectrum regions.
Distinguish ionising from non-ionising radiation and apply this to mobile phone safety claims.
Evaluate a scientific claim using evidence from the EM spectrum.

Warm Up

Sort it!

Write each application or hazard from the pool into the correct EM wave category in the table below. Each item belongs to exactly one category.

Wi-Fi transmission Thermal imaging Sunburn AM broadcasting Bone imaging TV remote control Forgery detection Cooking food Sterilising medical equipment (gamma) Cancer treatment (radiotherapy) GPS satellite signals Photography

EM wave type	Applications / hazards from the pool
Radio waves
Microwaves
Infrared
Visible light
Ultraviolet
X-rays
Gamma rays

Go Deeper

Evaluate the claim

Someone claims…

“Mobile phones are dangerous because they emit radiation. Everyone knows radiation causes cancer — the same thing that makes X-rays dangerous makes phones dangerous. We should ban children from using phones entirely because the radiation will definitely give them cancer.”

(a) Classify the type of radiation that mobile phones emit. Explain where it sits on the EM spectrum and whether it is ionising or non-ionising. Define what ‘non-ionising radiation’ means.

Challenge 3 marks

(b) Compare the energy and ionising ability of mobile phone radiation (microwave) to UV radiation and X-rays. Use the EM spectrum to explain why X-rays are more dangerous than microwaves for causing cancer.

Challenge 3 marks

(c) Evaluate whether the claim that phones “will definitely give children cancer” is scientifically justified. Identify what is misleading in the claim and explain what type of evidence would be needed to properly assess the risk.

Challenge 3 marks

Wrap Up

In one sentence, what was the main idea of this lesson?