1. Think back to last big teach...

2. Remember..
Last time we look at some of the properties of waves. Used terms such as wave length and frequency.
Now we will apply our understanding.
Topics in physics are often not stand alone, they link with other topics!

3. P1- Topic 2 Big Teach The Electromagnetic Spectrum

4. Specification Link

5. Specification Link

6. Herschel and Ritter...

7. Herschel
Ritter
Ideas behind experiment
How was the temperature of the different parts of visible light different
Experimenting with Silver Chloride for photography, Knew that it turned black when exposed to light.
Equipment used
Prism
Thermometer
Light
Silver Chloride
Observations
Was hotter towards the red end of the spectrum and even hotter beyond the red
Turned black faster towards violet and even faster beyond the violet
Conclusions from observations
Must be invisible light beyond the red part of visible light.
Must be invisible light beyond the violet part of visible light.
Name of type of wave discovered
Infrared
Ultraviolet

8. They have asked you to discuss two experiments, do one at a time!
Things to remember…
You can bullet point 6 mark questions, just make sure they are full sentences using correct scientific language
They have asked you to discuss two experiments, do one at a time!

9. An explanation including some of the following points Results obtained:
Herschel: temperature on thermometer
Ritter: speed of darkening of silver chloride paper
Trend of results:
Herschel: hotter towards red end
Ritter: quicker towards blue/violet end Extension of experiment to get more results:
Herschel: measure below red; found it even hotter
Ritter: measure above blue/violet; paper darkened quicker
Conclusion: · Herschel: Must be radiation below red ( Infra Red) · Ritter: Must be radiation above blue/violet ( UV)  

10. ELECTROMAGNETIC SPECTRUM
740nm
370nm

11. The Electromagnetic Spectrum Key points you need to know...
Electromagnetic waves that have long wavelengths have lower frequencies and less energy.
And electromagnetic waves that have short wavelengths have high frequencies and high energy.
LEARN THE ORDER!!
Rich Men In Vegas Use eXpensive Gadgets (learn the order!) Think of your own pneumonic.

12. Electromagnetic Wave
Uses
Danger
Radio Waves
Telecommunications
Radio
None
Microwaves
Heating food
Mobile phones
Heat human body cells
Possible link to brain tumours via mobile phone use. But no evidence
Infrared
Heating
Night vision
Remote controls
Skin burns
Visible Light
To see
Ultraviolet Rays
Tanning Salons
Detect forged bank notes
Identify stolen goods
Skin cancer (mutations)
Cataracts
X-Rays
Detecting bones
Airport security
Ionising radiation- cell mutations that can cause cancer
Gamma Rays
Treating cancer
Sterilising food

14. Not always so simple!

15. Key words… wavelength, frequency, energy

20. Ionising radiation?

21. Ionising Radiation...
Gamma is Ionising- that means when it comes into contact with atoms it will make them lost electrons.

22. Why is this bad?
We are made up of atoms. When atoms lose electrons they become ions. Ions are reactive.
This causes the cells to mutate (because they are made up of atoms), which can lead to cancer!

23. Is Gamma the only type of ionising radiation?

25. What you need to know...
Ionising radiation is emitted by radioactive sources.
Alpha, beta and gamma are all ionising.
Alpha and beta are particles and gamma is a wave.
Ionising radiation can knock of electrons in atoms which can lead to cell mutation and eventually cancer.

28. Want more questions?
Past papers on singhscience and an exam booklet which is split up into the 6 different topics in P1.