This food experiment uses soda to show how gases expand when pressure decreases. Take two large 20-ounce bottles of soda. Shake up one of the bottles vigorously. Then open the bottle immediately, over a sink, making sure that nobody is in the way. The soda will fizz out of the bottle. With the second bottle, shake it a bit, and then tap it on the sides and the bottom to get rid of bubbles. When you open the bottle, there should be much less fizz than the first bottle produced.
Pour 2 percent milk into a glass. Place drops of different colors of food coloring at the glass’ sides. Then introduce a drop of vegetable oil into the middle of the glass. Be careful not to shake the glass, or the table you place it on. After awhile, the colors will start swirling and mixing, producing a colorful display. This comes about as the oil, which dissolves in the milk fat, creates a current.
Have children write something on a piece of blank, white typing paper, using a brush and lemon juice. Let it dry. Then if you hold the piece of paper up to a light bulb, the writing will appear in brown color. This chemical experiment will create a magical effect for the children.
Fill a glass jar three-quarters full. Add 2 tablespoons of baking soda and mix it in well. Then add one to two drops of food coloring and a few kernels of popcorn. Next, mix in a few drops of vinegar and after a few minutes the popcorn will move around, as if dancing.