Best Detergent for Removing Stains By - John Q. Somebody Purpose This experiment will test different brands of laundry detergent to see which is best at removing stains from white clothing. Underarm stains will be measured on a black-to-white scale before and after washing. Ketchup stains will be measured on a red-to-white scale. Procedure I washed four white t-shirts with underarm stains in ½ cup of Cheer, Tide, Gain, or no detergent. Right and left underarms were compared to a black-to-white (1 to 10) shade scale before washing and after washing. I subtracted the beginning shade (lower number) from the ending shade (higher number) to get the “number of shades improved.†Then I took the average of that number for left and right arms. I stained the same shirts later with 1/8 tsp. of ketchup for 15 minutes. The ketchup was wiped off and then the shirts were dried overnight. I washed the shirts in ½ cup of Cheer, Tide, Gain, or no detergent. The stain was compared to a red-to-white (1 to 10) shade scale and subtracted just like before to get the “number of shades improved.†The independent variable in both experiments was the brand of detergent. The dependent variable was the “number of shades improved.†Control variables for both included using ½ cup of detergent and washing in cold water. The staining process was another control variable for the ketchup experiment. In both cases the “no detergent†wash was a negative control. The experiment didn’t need a positive control. Hypothesis Cheer will have the highest “number of shades improved†on the black-to-white scale. Gain will have the highest “number of shades improved†on the red-to-white scale. Results In the black-to-white comparison the shirt was slightly cleaned just by using water. (Remember that a low number means “dark†and a high number means “light.â€) Tide did not perform much better than water alone. Cheer and Gain both tied for highest number of shades at 2.5 each. It is also interesting that the shirts themselves had different levels of starting shade, between 4 and 6. (See Table 1.)
Detergent Starting Shade (L/R) Ending Shade Avg. Shades Improved
None 4/5 5/5 0.5
Cheer 4/4 7/6 2.5
Tide 5/6 6/7 1.0
Gain 5/4 7/7 2.5
Table 1. Black-to-White shades of underarm stains. In the red-to-white comparison of ketchup stains the shirt was cleaned a lot (2 shades) just by using water. This was expected because the stain had just been made and not washed yet. Cheer and Gain both improved the cleaning by one more shade. Tide performed the best by removing the stain by 4 shades. Unlike before, the starting stains were much more regular, ranging only between a 2 and a 3.
Detergent Starting Shade Ending Shade Shades Improved
None 2 4 2
Cheer 2 5 3
Tide 3 7 4
Gain 2 5 3
Table 2. Red-to-White shades of ketchup stain. Conclusions I predicted that Cheer would perform the best on a black-to-white scale and I was partially correct. It tied with Gain for the highest number of Shades Improved. However, I noticed that all three shirts washed with detergent ended on a 6 or 7. Since the Tide shirt started the cleanest (5/6 compared to Cheer at 4/4), it didn’t have as big of a chance to clean. It’s possible Tide would have performed equally well if given equally stained shirts. I expected Gain to perform the best on the ketchup stains, but I was surprised to see that Tide was the best. It had both the highest Shades Improved score and the cleanest ending shade at a 7 compared to Gain and Cheer at a 5. Remember that high numbers mean whiter clothing. For a future experiment, I would like to use the same brand of detergent, but test the effect of leaving the stain longer before washing. I would also like to test how pre-treating the stain with detergent helps
to reduce the amount of final stain. I might want to also try to add in the cost per tsp. as a control variable as some detergents are more “concentrated than others. Pictures
Picture 1. Shirt before washing with Cheer.
Picture 2. Shirt before washing with black-to-white scale. This shirt scored a 4.
Picture 3. Ketchup staining a shirt for 15 minutes.