Use the survey meter to show that
these
items are radioactive.
NOTES
Uranium trioxide was used as a
colorant
in the glaze on red Fiestaware plates made before 1969.
From the 1920-60's, luminous watch
and clock faces were painted with a mixture containing radium-226 to
make
them glow in the dark.
Some fraction of the potassium
in
salt substitute (KCl), bananas, etc. is potassium-40, a beta emitter.
Smoke detectors contain
americium-241,
an alpha source, used to ionize the air so that it conducts. When
smoke enters the chamber it combines with the dust particles, reducing
the current and setting off the alarm.
Old gas lantern mantles contain
thorium-232, which is thermoluminescent (it glows when heated) and
allows
the mantle to emit light at a relatively low temperature.
