“Radioactivity in Everyday Life – It’s Closer Than You Think”

“It’s invisible, silent, and you certainly can’t smell it… but radioactivity is all around us.”

This week in the lab has been a particularly enjoyable one, running radioactivity sessions with students. Not because we were handling dangerous sources — quite the opposite — but because we were exploring just how ordinary radioactivity can be.

Out came the Radiacode app and handheld detector, and instead of sealed lab sources, we investigated items you could (in theory) buy or already have at home.

What did we test?

• A thorium-enriched welding rod
• Small uranium-glazed pottery shards (from an old cup)
• Vintage watch hands painted with radium
• A standard household smoke alarm

Each one tells a story.

The welding rod gives off a steady, measurable count. The uranium glaze — once popular for its bright colour — quietly ticks away. And those old watch hands? A reminder of a time before we fully understood the risks.

Then comes the surprise…

The Smoke Alarm

Yes — it contains a radioactive source (americium).

But when measured?

The count is barely above background.

Why? Because the source is properly shielded and safely contained. It’s a brilliant real-world example of how radioactive materials can be used safely in everyday devices.

Why this approach works

I deliberately avoid using “dangerous” lab sources where possible.

Instead, I focus on:

• Real-world objects
• Safe exposure levels
• Understanding rather than fear

Students quickly realise:
Radioactivity isn’t just something in nuclear power stations
It’s part of the world around us

And crucially:
Risk depends on exposure and shielding, not just the presence of a radioactive material

The takeaway

By the end of the session, students aren’t just measuring counts — they’re thinking like physicists:

• What type of radiation is this?
• How is it being shielded?
• Should we be concerned?

And perhaps most importantly…

Not everything radioactive is dangerous — but everything should be respected.