This experiment from DoScience shows students how acidity and alkalinity affect a testing material. While both acids and bases become increasingly caustic the farther they are on the scale from a neutral pH, they also have different effects. After chopping up some red cabbage and throwing it in a blender with some water, you can put some juice into two bowls. Vinegar and baking soda are tried-and-true examples of acid and base that will show you the difference in reaction.
This experiment comes from Ernestine C. Davis' classroom at Chicago's Horace Mann Elementary School. Adding food coloring to water allows students to visualize relative strength of solution; as you add more coloring, the tint should strengthen. If you follow up the food coloring with bleach, the stronger the solution, the longer it should take the bleach to bring the water back to a clear state.
A chemical reaction requires that all the reacting substances come into contact with each other. Temperature measures kinetic energy, or the speed at which particles move. The higher the temperature, the higher the speed of these particles. With some effervescent antacid tablets and three glasses, you can test the difference between reaction rate for cold water, lukewarm water and hot water by clocking the time it takes for the tablet to dissolve in each environment.
Several websites offer students the chance to learn about chemical reactions through interactive learning. One of these sites is the Cork Rocket experiment, available through the PBS website. Using what you already know about acids and bases, students can mix the right chemicals to send a cork flying into the air.