Nuclear Turntables

Discovery of Radioactivity

Radioactivity was discovered over 100 years ago by Marie Curie and her husband Pierre, who found that something was being emitted by certain materials; a new kind of energy! Their discoveries created a huge amount of excitement at the time as it was believed that such a powerful new source of energy must be very beneficial. Marie Curie was the first woman to win a Nobel Prize for discovering radioactivity in 1903.

Benefits of Radioactivity:

Radioactivity has many beneficial uses. Please click on the links below to learn more about how radioactivity benefits society.

Risks of Radioactivity

For a long time, people didn’t understand the potential risks associated with radioactivity. For example, in 1903 Pierre Curie tied a chunk of radium (a highly radioactive material) to his arm for 10 hours. After seeing the severe burns left behind he decided that he had discovered a cure for cancer when all he had done was severely damage his skin. Issues with radioactivity:

• It can damage cells and DNA – High doses can increase the risk of cancer
• It can remain radioactive for a long time – While some radiation is short-lived, some radiation can last for thousands of years. This is a problem if the radioactive material is released into the environment.
• You need special equipment to detect it – You can’t see, hear, smell, taste or feel radioactivity.

However, when handled correctly, radioactivity can be used safely and is quite useful. For some time after Marie Curie’s discovery, a range of dangerous and ridiculous radioactive products were sold to the public – everything from “re-invigorating” Radium water to toothpaste that had Thorium in it; both of which are highly radioactive. The scary thing was that since people didn’t know how dangerous they were, companies claimed that using them would make you healthier when in reality they were dangerous and could cause cancer.

What is radioactivity?

In this FAR Lab experiment you will monitor the radiation from four real radioactive samples; an alpha source, a beta source, a gamma source and an unknown source. Three very different kinds of radiation come from radioactive materials: – “alpha”, “beta” and “gamma”. A radioactive sample of each type can be selected, as well as an “unknown” radiation type which you will try to determine. We are also interested in how the barriers affect the radiation. That is, which barriers can the different types of radiation pass through and which barriers are they unable to pass through. All radioactive emissions are potentially very harmful to humans so it’s important to know this.

To begin the experiment, open an experiment station from the list below, and log in with the student access code provided by your teacher.

Station: 1 Station: 2 Station: 3 Station: 4 Station: 5 Station: 6 Station: 7 Station: 8

PART 1: Alpha Radiation

1. In the column with the Source buttons, click on the "Alpha" source.
2. In the column with the Absorbers buttons, click on the "None."
3. Make at least five recordings of the counts and make a note in your lab books.
4. Wait for your Count History graph to record at least 30 seconds of data then create a PNG image.
5. Repeat this process for the "Plastic", "Thin Aluminium", "Thick Aluminium" and the "Lead" absorbers. Make sure to leave some time for the graph to stabilise after you change your absorber.
6. Find the average number of counts for each barrier by averaging your recordings of the counts.

What did you notice when you went from no barrier to a barrier?

PART 2: Beta Radiation

1. In the column with the Source buttons, click on the "Beta" source.
2. In the column with the Absorbers buttons, click on the "None."
3. Repeat steps 3-6 that you did for the Alpha source.

What do you notice when you go from no barrier to the different kinds of barriers?

Was there a difference between the thin and thick piece of Aluminium?

Can radioactive beta material be safely stored?

PART 3: Gamma Radiation

1. In the column with the Source buttons, click on the "Gamma" source.
2. In the column with the Absorbers buttons, click on the "None."
3. Repeat steps 3-6 that you did for the Alpha source.

Does anything affect the average number of counts for gamma radiation? If so, how?

PART 4: The Unknown Source

1. In the column with the Source buttons, click on the "Unknown" source.
2. In the column with the Absorbers buttons, click on the "None."
3. Repeat steps 3-6 that you did for the Alpha source.

Which kind of radiation is the most difficult to contain? Why?

Which kind of radiation is the easiest to contain? Why?

If you discovered that an Aluminium container of radioactive beta material was still emitting radiation, how could you reduce the radiation emitted?

What do you think the unknown sample is? Alpha, beta or gamma? Can you explain why?

The unknown sample has been taken from a smoke detector, where there is a radioactive sample a short distance from a radiation detector, which is open to the air. How does a smoke detector work?

Gamma radiation is highly penetrative and may require heavy shielding. Can you describe one beneficial use of gamma radiation?

Which is the safest kind of radioactive material to handle and why?

thats all folks!