Making chalk that will write invisible messages on the chalk board—and then appear "magically."
Use chalk that is as pourous as you can get (cheapest chalk is usually the most pourous).
In a saucepan heat and stir -
1/2 cup water
1 cup sugar
Once the sugar has desolved you have supersaturated sugar water.
Use a small jar (a junior baby food jar works well) and put several
sticks of chalk into it. Fill the jar with the sugar
water. The chalk will NOT dissolve. Let sit for
several hours so the water can soak into the chalk.
you are ready to use the chalk take out a stick, put it near the
chalk board and when you are ready write your message on the chalk
board. The writing will, at first, be invisible but as the
"chalk" dries on
the board it will be come visible. The chalk should be replaced
in the jar so it stays relatively moist, for use again at sometime in
-- from white to purple and back again. When iodine is
mixed with starch the chemical reaction causes the starch to turn
a deep purple. When that same spot is saturated with fruit juice
that is enriched with vitamin C the spot disappears.
Obtain "tincture of iodine" from the drug store. Put a slice of
bread on a white paper towel --drop some of the iodine onto a slice of
white bread. The spot will turn a bright purple - later
pour some vitamin C enriched juice (white grape - you can pass it off
as water) and the spot will disappear.
Science Experiments (Tricks) that can be REAL magic.
Churchill, E. Richard, et. al. (1997) 365 Simple Science Experiments with Everyday Materials. Black Dog & Leventhal Publishers.
Potter, Jean. (1995) Science in Seconds for Kids: Over 100 Experiments You Can Do in Ten Minutes or Less. Jossey-Bass.
Provenzo, Eugene F. (1989) 47 Easy-to-Do Classic Science Experiments. Dover Publications.
Robinson, Tom. (2001) The Everything Kids' Science Experiments Book: Boil Ice, Float Water, Measure Gravity-Challenge the World Around You! Adams Media Corporation.