1. More about alpha, beta & gamma radiation (7.4)
LO: We are learning about properties and dangers of radiation
I Can:
DESCRIBE how far each type of radiation can travel in air & other materials
DESCRIBE the ionising power of alpha, beta and gamma radiation
Explain why alpha, beta and gamma radiation is dangerous
STRETCH: Apply penetrating ability of alpha, beta, gamma radiation
to medical and industrial uses.
I have learned…

2. 7.4 More about alpha, beta, gamma radiation.
DESCRIBE how far each type of radiation can travel in air & other materials
DESCRIBE the ionising power of alpha, beta and gamma radiation
EXPLAIN why alpha, beta and gamma radiation is dangerous
APPLY penetrating ability of alpha, beta, gamma radiation to medical
and industrial uses
4 - 6
4 - 6
4 - 6
6- 8
Keywords & units
Count rate
Background radiation
range
ionisation
irradiation
radioactive
Ionising Radiation
exposure
Peer review
Starter
Demo properties of radioactive sources (only if permitted to do so )
Complete wsheet page 1
Main Activity
Describe some sources of background radiation
(and the need to subtract background count from all data measurements
Work through the PPT completing the FDN wsheet on page 2
Plenary
Check answers to questions from Wsheets and TXBK
Show some of the teachers TV clip
Homework task TXBK Q p or use ‘EDUCAKE’

5. This is ionising radiation from: cosmic rays (from outer space) 13 %
Background radiation
This is ionising radiation from:
cosmic rays (from outer space) %
X ray tubes %
radon gas from granite rocks %
food and drink %
air %
nuclear reactors leaking %
nuclear weapons testing %
Ionisation is the removal of an electron from an atom
leaving it as a positively charged ion
Experiment to measure Background count rate /min: *

6. Uses of Radioactivity • Measuring the thickness of foil
• Radioactive tracers to monitor the working of organs in the body
• Smoke alarms
• Radioactive tracers to look for water leaks

7. Measuring the thickness of Foil
Radiation source
Aluminium foil 2mm thick
Inside a foil factory
Radiation Detector
What would happen to the reading on the radiation detector if the foil got thicker? What would then happen to the gap between the rollers?
Would you need an isotope with a long or short half-life? Explain why.
What type of radiation would be most suitable for this job? Explain why.

8. Radioactive tracers to monitor the working of organs in the body
Radioactive iodine is drunk by the patient to find out if their kidneys are blocked.
What do the traces tell you about this patients kidneys?
What properties must the radiation used in this test have? (Hint: think type and half-life.)

9. Smoke alarms
Radiation source
Radiation detector
Which type of radiations would be most suitable for this use? Explain why.
What effect does the smoke have on the level of radiation reaching the detector?
Would the radiation source need a long or a short half-life?
smoke

10. Radioactive tracers to look for water leaks
Radiation detector

11. + Ionisation  particle
When radiation collides with neutral atoms it alters their structure by knocking off electrons. This will leave behind IONS – this is called IONISING RADIATION which can damage or kill living cells
 particle
Electron +
Irradiation: occurs when an object is exposed to radiation, but the object itself, does not become radioactive.

12. Minimising exposure and cancer risk

13. Alpha, beta and gamma radiation

14. + Irradiation  particle
An object becomes irradiated if it is exposed to ionising
Radiation. The object itself does not become radioactive .
 particle
Electron +