Lesson 3 - Intro to Radioactivity

All information from Mr Menzies-Wilson's first lesson on Intro to Radioactivity taken place on Tuesday 9th September 2025

What is an isotope?

An isotope has the same number of protons but a different number of neutrons

What is an ion?

an atom that has too many or too few electrons, it is positively or negatively charged

How does radioactivity occur?

• Some isotopes are unstable, this makes them radioactive.

• It means their nucleus will change into a different more stable nucleus.

• As they do so, they emit ionising radiation

Which kinds of ions are unstable?

isotopes not in the periodic table

What is ionising radiation called?

radioactive decay

What can ionising radiation do?

cause cancer or damage cells

How can ionising radiation be detected?

geiger tube and counter

How does a geiger counter work?

It beeps and counts up each time an ionising radiation is detected

How to be safe when handling radioactive sounrces?

• Wear gloves to make sure there is no contamination with radioactive material on my hand

• Use tongs when handling sources to make sure there is a safe distance so you get less radiation

• Check radioactive source for cracks. Never use a radioactive source that is cracked as you don’t get contamination