Stained Laundry Science and Bleach
With a guided science activity, students can get a firsthand look at how bleach helps remove colored stains from laundry. Are some colors harder to remove than others? Put it to the test!
Grass, mud, spaghetti sauce, grape jelly, mustard... all of these can leave stains on your white clothes that can be difficult to get out, and there are all kinds of other stains you might end up with in the course of a regular day. Whether you spill something, drop something, fall in something, or bump into something, your clothes can wind up with visible markers of the day—stains. And stains come in all colors!
How do you get stains out of your clothes? By doing the laundry, of course! But what is it about "washing" clothes that makes stains go away?
The Science Behind Stain Removal
There is chemistry at hand in the formation of stains as well as in the process of removing them. With this family- or classroom-friendly science activity, kids can learn more about the relationship between the stains we see and molecules, visible wavelengths of light, chromophores, color, and chemical reactions. Once students have a better sense of what makes a stain visible (or colored), they can experiment to see the power of bleach in action.
Most household bleach contains an oxidizing agent, which causes a chemical reaction. When bleach reacts with a stain molecule, the chemical structure of the stain molecule's chromophore changes—and the visible stain disappears. The Battling Stains with Bleach science activity guides students in a hands-on experiment using tap water, food coloring, and bleach. In this activity, students observe the reaction that occurs when bleach is added to solutions containing different colors of food coloring, a visible reaction that simulates what happens when bleach interacts with colored stain molecules in the laundry.
Do all colors of food coloring respond the same to bleach? Why or why not? If they don't all respond the same, what might you need to do to remove some stains compared to others? What variables may change how well bleach works to remove a stain? Can you use bleach with all of the laundry? Why or why not?
Find out the answers to these and other stained laundry questions with a hands-on science exploration!
Students interested in science related to this activity (including science related to variables that may alter the speed of a chemical reaction), may enjoy the following projects and posts at Science Buddies:
- Quick and Dirty Science—Testing Laundry Detergents (a Science Buddies in Action success story!)
- Are Enzymes in Laundry Detergents Effective Stain Removers? *
- Plop, Plop, Fizz Fast: The Effect of Temperature on Reaction Time
- Big Pieces or Small Pieces: Which React Faster?
- Can You Change the Rate of a Chemical Reaction by Changing the Particle Size of the Reactants?
- How Fast Does an Alka-Seltzer® Tablet Make Gas?
- Solar-powered Chemistry: Study Chemical Reaction Rates in Ultraviolet Beads