1 of 6 © Boardworks Ltd 2006

The EM Spectrum

11 April 2023

Objectives

Be able to describe the order of the em-spectrum and know how fast light

travels. HSW: AF5: Process data using multi-step calculations to identify complex relationships between variables.

Used before in: Will use again in:

PLTS: Independent enquirers: support conclusions, using reasoned arguments and evidence.

Used before in: Will use again in:

KeywordsWavelength, lamda, amplitude, frequency, Hertz, kilohertz,

megahertz, speed, metres, kilometres.

2 of 6 © Boardworks Ltd 2006

Outcomes

All students should be able to: Describe that there are different types of

visible and invisible light each with different properties.

Most students should be able to: State the speed of light.Some students should be able to:Explain that the em-spectrum can be

described in different sections because of different wavelengths and frequencies and that this effects how much energy the light has.

3 of 6 © Boardworks Ltd 2006

4 of 6 © Boardworks Ltd 2006

Electromagnetic Radiation

E-M radiation is basically a movement of energy in the form of a wave. Some examples:

5 of 6 © Boardworks Ltd 2006

Practical Time

• Dispersion practical.

• Can you split light up?

• What do you see?

• Now watch the demo

• Draw what you see (how can you remember what you see?)

6 of 6 © Boardworks Ltd 2006

The Electromagnetic Spectrum

• Demonstration

• Your teacher will show you the EM-Spectrum and describe the sections.

• How do we know they are all there?

• Why aren’t there any more than this?

7 of 6 © Boardworks Ltd 2006

The Electromagnetic Spectrum

Gamma rays

X-rays Ultra violet Visible light

Infra red Microwaves

Radio/TV

Each type of radiation shown in the electromagnetic spectrum has a different wavelength and a different frequency:

Each of these types travels at the same speed through a _______ (300,000,000m/s), and different wavelengths are absorbed by different surfaces (e.g. infra red is absorbed very well by ___________ surfaces). This absorption may heat the material up (like infra red and _______) or cause an alternating current (like in a __ _______).

Words – black, microwaves, long, short, TV aerial, vacuum

High frequency, _____ wavelength

Low frequency, _____ (high) wavelength

γ

8 of 6 © Boardworks Ltd 2006

Order of EM Spectrum

• R

• M

• I

• V

• U

• X

• G

• Randy

• Monkeys

• In

• Velvet

• Underpants

• Xterminate

• Gibbons

• Radio

• Microwaves

• Infra-red

• Visible

• Ultraviolet

• X-Ray

• GammaYour turn – come up with your own

9 of 6 © Boardworks Ltd 2006

X-rays Ultra violet Visible light

Gamma rays

Microwaves

Infra red Radio/TV

γ

BAKER’S “PLAY YOUR EM CARDS RIGHT”

TRY AGAIN

Is the Wavelength Higher or Lower?

10 of 6 © Boardworks Ltd 2006

X-rays Ultra violet Visible light

Gamma rays

Microwaves

Infra red Radio/TV

γ

TRY AGAIN

higher

11 of 6 © Boardworks Ltd 2006

X-rays Ultra violet Visible light

Gamma rays

Microwaves

Infra red Radio/TV

γ

TRY AGAIN

higher

12 of 6 © Boardworks Ltd 2006

X-rays Ultra violet Visible light

Gamma rays

Microwaves

Infra red Radio/TV

γ

TRY AGAIN

lower

13 of 6 © Boardworks Ltd 2006

X-rays Ultra violet Visible light

Gamma rays

Microwaves

Infra red Radio/TV

γ

TRY AGAIN

higher

14 of 6 © Boardworks Ltd 2006

X-rays Ultra violet Visible light

Gamma rays

Microwaves

Infra red Radio/TV

γ

TRY AGAIN

lower

15 of 6 © Boardworks Ltd 2006

X-rays Ultra violet Visible light

Gamma rays

Microwaves

Infra red Radio/TV

γ

TRY AGAIN

higher

16 of 6 © Boardworks Ltd 2006

The Electromagnetic Spectrum

Gamma rays

X-rays Ultra violet Visible light

Infra red Microwaves

Radio/TV

γ

The correct order – how can we remember it?

17 of 6 © Boardworks Ltd 2006

Hotseat