Can a banana be radioactive?

Predict, before you measure

Rank the samples from most to least radioactive

Drag to reorder, or tap the arrows on mobile. Put the one you think will give the most tracks at the top. Then lock in your ranking.

• ↕ 1 Banana or banana peel
• ↕ 2 Pistachios
• ↕ 3 Chickpeas
• ↕ 4 Potato with skin
• ↕ 5 Low-sodium salt (KCl)
• ↕ 6 Ground coffee

Lock in my ranking

Ranking locked. You will compare it with your results at the end.

Why did you rank them this way? Write your reasoning.

Extra question. You measure the banana for the same time as the empty room. Compared with the background count, the banana gives...

Lock in my answer

Prediction locked.

Extra question. Two groups measure the same sample for the same time. Their counts will be...

Lock in my answer

Prediction locked.

Observe

What did the detector record?

Background tracks in 15 min

Sample	Tracks in 15 min	Main track type(s)	More than background?

Track types, dot = photon, worm = electron (beta), blob = alpha, straight = muon.

Explain

What does it mean?

Which samples were measurably radioactive? Did the result match your ranking? Most of the active samples are rich in potassium. Explain the link and think about potassium-40. Does "radioactive" mean "dangerous" here? Give your reason.