The simplest chemistry experiment is changing water into vapor or ice. Add salt to the water to change the freezing temperature and determine what the new freezing temperature is. Test other household substances such as sugar or baking soda to determine if they affect the boiling or freezing point of water. Make “gluep” or “gak” to study a plastic that seems somewhere between a solid and a liquid. Observe the properties of gasses by using carbon dioxide to blow up bubbles that will sink.
Chromatography, a process to separate mixtures into identifiable parts, lets you study the colors in common foods. Separate Skittles, M&M’s and Kool-Aid into their component colors using a salt solution and a coffee filter. Test other items such as permanent markers and water-soluble markers to determine if the colors are different.
Other chemical reactions create light. Use a glow stick to study how temperature affects the chemical reaction that causes the glow. Submerge the stick in cold water, warm water and finally place it in a freezer.
Chemical reactions may create heat and/or flames—household matches are an example of this. Adding different chemicals can change the color of the flame. Boric acid will turn flames green, table salt will make flames yellow and potassium chloride (a salt substitute) will make purple flames. Other chemical reactions can cause explosions. Volcanoes are a traditional favorite of science fairs. The combination of water, baking soda and vinegar in the correct proportions creates a volcanic explosion. A similar explosion comes from mixing Mentos mints and soda pop.
Provide adult supervision for experiments involving heat or fire, and review directions thoroughly before you begin. Some experiments, such as the volcano, will be extremely messy. Prepare your workspace in advance to reduce mess and ease cleanup when the experiment is over.