Chemical reactions that produce a visual result are a source of amazement for many students. These types of projects allow students to see firsthand how two chemicals interact with each other and the effect that the combination of the two achieves. Teachers can demonstrate chemical reactions to students using an inexpensive combination of tap water, food coloring, bleach and baking soda. Using only these ingredients, teachers can both create colored water and return it to its original clear color.
Fill the clear containers with 1 cup of room temperature water each.
Add four drops of food coloring to each container. You may use whatever color food coloring you wish. To add to the excitement to the experiment, place a different color in each container.
Stir the liquid in each container until the color is completely incorporated.
Select the bleach-only method or the faster-acting baking soda method.
Add bleach with the eye dropper four drops at a time.
Stir the solution after each addition.
Continue adding bleach until the color has complete dissipated.
Ask students to count the drops of bleach necessary to eliminate the color.
Extend the experiment by asking students to compare the amount of bleach needed to remove each color. This allows students to determine if one color of food coloring is in fact more potent than the others.
Add four drops of bleach to each container using an eye dropper. Upon the addition of the small quantity of bleach, you will notice the color begin to fade.
Add 1 tsp. baking soda to the solution.
Stir the solution. As you mix the baking soda, you will notice that the color has completely disappeared and the water is, once again, clear.
Extend the experiment by discussing the properties of water and creating a hypothesis to explain why the baking soda had such dramatic effects on the liquid.