Teach your child that things are not always as they seem.

Take a glass, and fill it to the brim with dry beans. Ask her if you can put anything else into the glass. If she says no, take some salt (or sugar or sand) and pour it into the glass. Shake the glass a little, and pour more salt, so the cracks are filled with salt. Again, ask her if you can put anything else inside . If she says no, take some water, and pour it into the glass.

This gives her a different way of looking at things. Plus, it seems like a magic trick that she can try on others in the family!