Starter Postit What do you know about radioactivity

Starter – Post-it What do you know about radioactivity? DA N GER O US

Learning objectives 1. Explain what a radioactive substance is & what makes a substance radioactive. 2. Explain how radioactivity can be detected. 3. Recall the different types of radiation that is emitted from a radioactive substance. 4. Explain what is meant by ‘nuclear decay’. Keywords: - Radioactivity - Unstable - Nucleus - Geiger counter 1 9

A Mystery…? A French physicist, Henri Becquerel left an object on top a piece of photographic film (in a paper wrapper) in his desk drawer. On top of the object he had left a packet of …? ? ? . . . salts. He later discovered that an image had developed onto the photographic film. What was the object? What exactly was in the packet? Explain your answer

A Mystery…? There were uranium salts in the packet that emitted a type of radiation which passed through paper but did not pass through the metal of the key. What next? A young physicist called Marie Curie investigated this further and found this radiation was being given out all the time, she described this as ‘radioactivity’. Marie Curie and her husband continued research in this area and discovered other radioactive elements. One named Polonium after Marie’s native country. What country is this? Poland

What is a Radioactive substance? A radioactive substance releases nuclear radiation which is a type of ionising radiation emitted from an unstable nucleus. Recall: 1)What is a nucleus? 2)What does ionising mean? 2) Ionising means to remove electrons from an atom and to therefore form an ion. 1) A nucleus is the centre of an atom. An unstable nucleus becomes stable by emitting nuclear radiation.

Detecting Nuclear Radiation How do you know if something is radioactive? Radioactivity can be detected using a GEIGER COUNTER. This uses a GEIGER-MULLER TUBE connected to a electronic counter. The counter clicks every time a radioactive particle enters the Geiger-muller tube. A Geiger counter measures ‘counts/clicks per minute’ (CPM). Strength of radioactivity is measured in a unit called Becquerels (Bq) Why do you think it is called a Becquerel?

Is all nuclear radiation the same? Are these symbols familiar? What do they mean? α β γ There 3 types of nuclear radiation: • Alpha radiation (α) • Beta radiation (β) • Gamma radiation (γ)

When does a material release radiation? Nuclear decay is a random event that occurs without anything being done to a nucleus. Nuclear decay will happen but it is not possible to predict exactly when - random.

Radiation – True or False Exposure to nuclear radiation makes you a super hero FALSE

Radiation – True or False Radioactive materials glow in the dark? TRUE & FALSE The energy that comes off of radioactive materials can give energy to nearby fluorescent materials which will then ‘glow’ Nuclear decay does give off waves but these are not the type you can see but do have a lot of energy. So radioactive materials do not glow themselves…. . but…

Radiation – True or False Nuclear Radiation can change your DNA? TRUE ‘VIDEO LINK’

Radiation – True or False Radioactivity is measured in units called ‘Becquerel’? TRUE

Radiation – True or False Bananas are radioactive TRUE ‘VIDEO LINK’

Radiation – True or False Eating bananas is dangerous FALSE …well safe if you chew properly.

Radiation – True or False Nuclear radiation is not useful FALSE

Radiation – True or False The word ‘nuclear’ is related to the nucleus of an atom. TRUE

Radiation – True or False Nuclear power provides around 1% of the world’s electricity. FALSE Nuclear power provides around 14% of the world’s electricity.

Radiation – True or False Radioactive waste produced by nuclear reactors is easy to dispose of safely. FALSE