Regardless of your religious affiliation, this is a good time of year
to stock up on food-grade dyes. The dyes in the Easter-egg kits:
a) are reasonably intense;
b) don't pose the classroom safety and/or disposal problems of
typical "industrial" dyes;
c) come in a wider range of colors than you usually see in food
coloring at other times of the year; and
d) are cheap and readily available.
It's nice to have dyes on hand. Applications include:
-- Color mixing. This is a subject where many incoming students
are plagued by misconceptions.
-- Diffusion demonstrations.
-- et cetera.