These mini aquariums make great boredom-busters on a day when your kids are waiting for the sun to come out.
Place the jar lid wrong side up on a flat working surface. Then use a small lump of clay to stick the bottom of each plastic item to the inside of the lid.
Fill the jar almost to the top with water, and stir in a few drops of glycerin and 1/2 teaspoon of glitter. The glycerin will increase the density of the liquid, so that the glitter will fall more slowly.
Add shells and a bit of aquarium gravel, if desired.
Finally, tightly screw the lid onto the jar. Then invert the globe and enjoy the glittery show.