Subject Science Key stage 4
Topic Area Physics: Electromagnetic spectrum Programme of study links
Objectives

To understand that the electromagnetic spectrum is a continuous range of electromagnetic waves that have different properties and can transfer energy
To understand that different types of electromagnetic waves have different uses and associated hazards

2a, 3a, 4a, 7c, 7d
Lesson plan context This lesson begins with a review of the visible spectrum and consideration of whether anything lies beyond the limits of what our eyes can detect. This serves as a stepping stone to introducing the electromagnetic spectrum and the different types of electromagnetic waves. Students will be familiar with most of these waves, but may not realise that they are all part of the electromagnetic spectrum and what properties make them behave in different ways. A series of clips provides real-life contexts for students to learn about the uses and hazards of the different types of electromagnetic waves. Students can work together in groups to gather information and demonstrate their knowledge by sharing information with other groups.
Teaching context Class and group work. The lesson can be carried out using the video clip and a projector/whiteboard. It is suggested that the first part of the ‘Main activity’ is carried out in groups, which will require the students to have access to computers in order to view the clips involved and use the internet. If access to enough computers is not possible, this activity can be led by the teacher instead. A worksheet is provided to help students record information from the recommended sources.
Notes on timing This lesson should cover 1-2 hours to allow students time to develop and apply their understanding of the electromagnetic spectrum. It could be extended by incorporating the homework activity or one of the extension activities in the classroom. If time is limited, the final part of the ‘Main activity’ could be omitted or carried out as an alternative homework activity.
Key question What are the uses and hazards of the electromagnetic spectrum?
Starter

Start the lesson with the clip Infrared radiation. First, watch up to 00:37 (“Is there anything beyond the visible spectrum?”) to start the students’ thinking from the familiarity of the visible spectrum.  Using the three questions provided, get the students to consider the nature of a spectrum and what might exist beyond the limits of the visible spectrum.

Next, to answer these initial questions, watch the rest of the clip Infrared radiation from 00:37 (“This probe is sensitive to electromagnetic radiation...”). The three prompt questions provide a focus for discussion and introducing the concept of the electromagnetic spectrum and the different types of electromagnetic waves. This provides an opportunity to find out how much the students already know about electromagnetic waves and leads into the ‘Main activity’ section.
Main Activity

Start the main section of the lesson with the clip Electromagnetic spectrum to introduce the names and order of the different types of electromagnetic waves.

Next, the students use the following series of clips and the Channel 4 Learning website The Electromagnetic Spectrum to find out about the wavelengths, uses and hazards of the different types of electromagnetic waves:
1. Microwaves and radio waves; 2. Looking for aliens; 3. Seeing in the dark: Using infrared;
4. Visible light; 5. Ultraviolet radiation; 6. Keeping cool and safe in the sun; 7. X-rays;
8. Catching smugglers using X-rays; 9. Using gamma rays; 10. Linear accelerator.

The Uses and hazards of electromagnetic waves worksheet includes a table for the students to record the information that they obtain from these clips and elsewhere.

It is suggested that the students work in groups to carry out this exercise. Each group can be assigned different types of electromagnetic waves to find out about. When they have completed this part of the task, organise the students to share the information they have gathered with other groups or simply to report back their findings to the whole class. This provides opportunities for the students to learn from their peers and to develop their communication skills and their understanding of the task.

Once the students have completed the table on the Uses and hazards of electromagnetic waves worksheet, they can use this information to answer the set of the questions at the bottom of the worksheet. This should lead to an understanding of how energy, wavelength and frequency are related.

Finally, use the clip Microwaves and radio waves to introduce the apparatus that could be used to investigate the transmission and absorption of microwaves. Students can plan experiments in the context of public concerns about mobile phone masts and handsets. (If time and equipment permit, get the students to carry out their planned experiments.)

Worksheet: Uses and hazards of electromagnetic waves

Plenary

End the lesson with the clip Transmitting television programmes, which incorporates the application of several different electromagnetic waves and provides a familar, real-life context to consolidate the students’ knowledge of the electromagnetic spectrum and how it affects their everyday lives.

The open-ended homework activity, ‘A Day in the Life of Dr. E. M Spectrum’, encourages creative thinking and allows the students to demonstrate the scope of their undersatnding of the uses and hazards of elctromagnetic waves.

Extension

Three possible extension activities are suggested:

1. Watch the clip Searching for alien life to find out how radio telescopes can be used to detect radio signals from the remnants of the Big Bang. Use the NASA website How Astronomers Use the Electromagnetic Spectrum to discover more about how different types of electromagnetic waves are used by astronomers to study the Universe. Annotate a diagram of the electromagnetic spectrum showing the position of these waves and what they are used for.

2. Many of the discoveries about the electromagnetic spectrum came from scientists investigating the nature of visible light. Use the internet, to carry out research and create a timeline showing when some of the main discoveries about the electromagnetic spectrum were made and who made them. You can use the following websites to start your research:

3. Electromagnetic radiation affects many different aspects of our everyday lives and there are many issues associated with the uses and hazards of the different types of electromagnetic waves. Use the 'Understanding Radiation' section of the Health Protection Agency's Radiation website to find out more about these issues.
Notes on differentiation

The results of the open-ended tasks – planning experiments and the account of ‘A Day in the Life of Dr. E. M Spectrum’ – will be differentiated by outcome. The group activity facilitates feedback from peers, which can be used to support lower ability pupils.

Functional skills English Creative writing.
Maths Understanding and comparing different units of length.
ICT Internet research.