Laundry is a basic part of life, and one that many people don't give a second thought to until they encounter a stubborn stain that they can't remove. You may want to consider testing out various detergents or methods of applying them for your science fair project. Next time you spill some ketchup on your shirt, you'll know exactly which detergent to reach for.

The most obvious science project you can do that involves laundry detergent tests which type of detergent is most effective at removing a stain. To test this, cut a cotton shirt into several identical squares and stain each one with an equal amount of a staining agent, such as tomato sauce, mustard or mud. Then, wash each square of fabric with a different type of detergent, following the directions on the detergent carefully. When you are finished, take pictures of the washed fabric and compare the appearance of the stains to see which detergent worked most effectively. If you are near a science lab or manufacturing company, you may want to ask to borrow their colorimeter for more accurate results.

When your gym socks have been especially stinky, or if your hiking pants have been covered in mud, you may have considered putting in more detergent than the bottle recommends. But will more detergent actually get a load of laundry cleaner, or will it just make the clothes overly soapy and hard to rinse out? To find out, you can do a project similar to the previous one, but soak each piece of clothing in muddy water instead of applying an actual stain. Then, wash each piece of clothing in a different amount of detergent--one slightly less than recommended, one exactly the amount recommended, one slightly more than recommended, and one much more than recommended. Compare the results to test whether the recommended amount of detergent is also ideal for thoroughly soiled clothing.

If you're looking for a more exciting way to test the impact of laundry detergents on clothing, then you may want to consider doing a science fair project on fire-resistant fabric. Buy some children's sleepwear that is labeled as fire-resistant or fire-retardant, and cut it into strips. Leave some of the strips alone and wash others in various types of detergent, some stronger than others. Label the strips to keep them straight. Next, try burning each strip and time how long it takes for each strip to ignite. The results of this project will show you whether washing fire-retardant clothing can strip it of some of its fire-resistant qualities.