
The table salt and Epsom salt;
The honey jar (particularly if it has been open for awhile); and
The walls of the freezer (if it's not the frost-free kind).
If not, how are they different?
Dissolve 1 teaspoon of salt in 1 cup of water.
Grown-up alert!
Heat the mixture over a low flame to evaporate the water.
What's left?
What shape are these crystals?
Take a circle of paper (use thin paper) and fold it in half. Then fan fold it. 
Make cuts along all the edges. Unfold them.
Grown-up alert!
Pour a cup of boiling water into a dish and add 1 3/4 cups of sugar. Stir until the sugar is completely dissolved. Prepare a jar or glass as shown.

Wash the paper clips and use clean string. When the sugar water is cool, pour it into the jar and put it where no one will move it. Hang the paperclips in the water and put the pencil on top of the jar.
Some crystals may form in a few hours. Some may grow to be half an inch on each side. To save them, take them out of the water and keep them dry. But they may disappear--they are good to eat.