Zusammenfassung der Ressource
Special Pigments
- Thermochromic pigments
change colour when heated
or become transparent when
heated or cooled.
- Different pigments change
colour at different
temperatures, so a mixture of
different pigments can be used
to make a colour-coded
temperature scale. These are
used to make basic
thermometers.
- Uses: Electric kettles - change
colour as the water boils. Baby
products such as bath toys and
baby spoons - if bath water is too
hot it changes colour.
- Thermochromic pigments can be mixed
with acrylic paint, giving a wide range of
colour changes. Example: mixing a blue
thermochromic pigment that loses its colour
above 27 degrees with a yellow acrylic
paint would give a paint that is green below
27 degrees and yellow above 27 degrees.
- Phosphorescent pigments glow in
the dark. They absorb natural or
artificial light and store the energy in
their molecules. This energy is
released as light over a period of
time.
- Uses of phosphorescent pigments:
Watches or clocks with
glow-in-the-dark hands.
- Radioactive paints glow for years without needing to be
'charged up' by putting them in the light. A lot of them were
considered not safe as they could give quite a dose of
atomic radiation. Phosphorescent pigments were
developed as a much safer alternative.