Shake it up: Biology students test detergents


Sheri Donaldson

Ready, set, shake. The students shook the bags until they were running out of breath. Watching eagerly, the students saw different results from each test bag and were surprised by the results.

Biology teacher Megan McMullen’s students tested the strength of various laundry detergents in a lab involving enzymes. The results showed that all detergents are not equal.

“When we were learning about enzymes during class, I was not fully understanding it,” freshman Addie Lathrop said. “However, when Mrs. McMullen told us that we were doing a lab, I knew that all of us would not only have fun learning about enzymes but that the lab was really going to help us understand the concept of enzymes.”

Students first got the first Ziploc bag, bag A, and put a piece of cloth stained with ketchup in it. The baggie was then filled with only water. Ziploc bag B contained another piece of cloth stained with ketchup, water and laundry detergent. Ziploc bag C contained a cloth stained with ketchup, water and Tide detergent.

“I was able to help put the baggies together in my group,” freshman Karla Dominguez said. “It was fun making each baggie different and filling the bags with the different substances of either just water or of different types of detergent.”

The students were placed in groups of three, each student holding either bag A, B or C. They were instructed to shake the bags for ten minutes.

“Not only was it really fun making each of the baggies, but it was also fun seeing all of the students shake the bags,” freshman Glori Cozart said. “It was cool seeing all the students really competitive and anxious for the ten minutes to go by so that they could see their results.”

After examining the stained cloth in each of the bags, the students noticed that the baggie containing the Tide detergent was the most successful in removing the ketchup stain.

“The baggie with just water was the least successful in removing the ketchup off the cloth; we could still see the huge ketchup stain,” freshman Jorge Castro said. “But the baggie with the laundry detergent and the baggie with the tide detergent were very similar with results, they both removed the ketchup.”

Through discussion and evaluating the results, the biology students learned that the tide detergent was most successful in removing the ketchup stain on the cloth due to the enzymes in that detergent.

“I knew before the lab that the bags with detergent would do the best job removing the ketchup stains, but I didn’t know which detergent would do a better job,” freshman Jeff Donaldson said. “I learned that the tide detergent did the best job taking the stain off because it had enzymes and the other detergent did not.”

The students were shocked with what they learned about detergents with enzymes but were now able to better understand the role of enzymes and understand the sole purpose of the lab, to help illustrate further the information over enzymes.

“I learned that enzymes break down bacteria and dirt, cleaning clothes better than detergents without enzymes,” freshman Jazlyn Early said. “I was surprised that not every laundry detergent uses enzymes, but I do understand and appreciate this particular lab in learning about enzymes.”