Does it dissolve?

We subscribed to the Magic School Bus Science Club when I found a half off coupon (making each kit ~$10/mo). J is a little young for the intended age group, but many of the experiments he can do with guidance. He gets so excited when he sees the Magic School Bus package on the doorstep. We usually do an experiment the following weekend (though we haven't done more than 1-2 before the next month arrives - they are saved for later use of course).

This month's experiment packet was on water. The experiment that we chose was Substances Dissolving in Water. We used their recommended mixtures and added another (see details of the experiment below). We also didn't use test tubes standing up in clay, as they recommended. Instead, we used custard bowls and mixed the substances with clean spoons.

Materials:
*6 custard dishes filled half way with water
*vegetable oil
*food coloring
*salt
*sugar
*sand

Hypotheses:
*Guess whether the material will dissolve (go away) when combined with water. A good way to think of it would be: can you separate out the material to get just water + material after you combined them? If you can't the material dissolved.

J's Hypotheses: Does the material dissolve?
*Water and oil: Yes
*Water and salt: No
*Water and sand: No
*Water and food coloring: Yes
*Water and sugar: Yes

Directions:
*Add a few drops of oil to one cup and stir.
*Add a few drops of food coloring to one cup and stir.
*Add a teaspoon of salt to one cup and stir.
*Add a teaspoon of sugar to one cup and stir.
*Add a teaspoon of sand to one cup and stir.
*Observe your matter. Did each one dissolve in water?
*Record your observations.

Results:
*Water and oil: No
*Water and salt: Yes
*Water and sand: No
*Water and food coloring: Yes
*Water and sugar: Yes

Oil at the top, water below (not dissolved)

J loved this simple science experiment. His hypotheses were all over the place, but now if he does this experiment in school, he'll know which material dissolves in water.

I can't wait to try other experiments from the Magic School Bus.