As children turn or shake the bottle, they can see animals that live on the desert. This is a great activity for visual discrimination. Seal the bottle. Attach a magnet to the top of the bottle by tying one end of yarn around the magnet, and the other to the bottle. Children discover what items are attracted to the magnet, and which are not, by rubbing the magnet along the sides of the bottle.
Children can record, or draw pictures to record their observations.
In the party shop at K-Mart, I found bingo materials. Packages come with a magnetic bingo wand, and colored magnetic discs. Add about 20 magnetic bingo chips to a bottle filled with water. Attach the magnetic bingo wand to the top of the bottle by using yarn. Children will enjoyed seeing how many discs they can pick up with the magnet, and enjoy watching them float to the bottle.