[DecentAI]

TIL that there readily available radioactive material/disks sold online…

[busyant]

I have taught a chemistry class where we use those disks. They have a stamp on them that say something like "NRC exempt quantity."

So, apparently, the disks have enough radioactive material to detect, but not enough to cause anyone to worry.

[quickthrower2]

Smoke detectors have radioactive material

[aceazzameen]

Not all though. Photoelectric detectors also exist and seem to be more common in homes these days.

[dr_dshiv]

TIL that you can buy antimatter on the internet.