INTRODUCTION

We always see ads on TV and magazines claiming to be the number one brand of dish soap. Instead of blindly trusting these advertisements we wanted to find out which dish soap is truly the most effective.

HYPOTHESIS

Our big question is what dish soap works the best and why. Based on our consumer research, we hypothesize that Dawn dish soap is the most effective at cleaning due to its widespread popularity, which reflects customer satisfaction, and its superior grease-cutting ability, which is attributed to its unique formulation of surfaces and chemicals.

RESEARCH

Preliminary Market Research - Although this is not scientific research, looking at online reviews of these products gives us insight on what other people think about these products as we are interested to see if our results match public opinions.

According to thousands of reviews the overall market results show that most consumers were most happy with the Dawn Platinum dish soap. We will keep this information in mind when concluding our experiment.

How does soap work and what is the best way to test how effective each dish soap is?  Dish soap contains surfactants that reduce the surface tension of the water and helps lift and penetrate the food particles to help clean the dishes.  The soap should help with cleaning almost immediately upon contacting the food but the longer it is in contact with the food particles and grease the better the soap will work at removing the food.  It is very hard to control the pressure and direction of scrubbing the soapy dishes, which is the traditional way to hand wash dishes, so we have decided to skip this method of cleaning and chose a method that could be easier to control all of the testing conditions.  We have decided to soak the dirty plates in soapy water and test how efficiently the soap penetrates the food stuck to the plate over equal time and under equal conditions.

VARIABLES

• Independent Variable: The brand of dish soap
• Dependent Variable: How well the dish soap works
• Controlled Variable: water temperature, amount of food on each plate, amount of soap, amount of mixing the soap into the water, same amount of sponge pressure on each the plate , same amount of time

PROCEDURE 

Step #1: Wash 5 plates thoroughly by hand and then dishwasher to ensure all plates are equally clean to start.

Step #2: Prepare food on 5 glass plates

Step #3: Let the plates sit for 30 minutes

Step #4: Pour 8 cups of water into 5 separate containers

Step #5: Add 1 teaspoon of each dish soap into the 4 containers, leaving 1 container with only water

Step #6: Mix the soap into the water by swirling the water 3 times

Step #7: Place 1 plate in each container and let sit for 15 minutes.

Step #8: After 15 minutes, remove each plate and place on a paper towel

Step #9: Using a new sponge for each plate, wipe 1 line with equal pressure down the center of each plate

Step #10: Photograph each dish and observe how dirty each plate is after being washed 

Step #11: Review the results and observe which dish soap works the best

OBSERVATIONS

Experiment #1 - Mac N Cheese served on a plate

OBSERVATIONS

Experiment #2 - Chili in the microwave for 30 seconds

ANALYSIS

To know which dish soap works the best we did two experiments to see which soap would come out on top. We prepared 5 equally dirty plates, then let it sit for 30 minutes. After waiting for the food to dry up, we soaked them in 8 cups of the equal temperature water and 1 teaspoon of dish soap for 15 minutes. We stirred the dish soap into the water with 3 circular motions. Once the plates were done soaking we used a sponge and dragged it with equal pressure down the middle of the plate to see the results.

To decide which soap works best we created 3 different judging categories, each of which we gave a score out of 10 (10 being the best performance and 0 being the worst).  These categories were smear, residue and chunks.  

CONCLUSION

OVERALL RESULTS

After doing our experiments, we can conclude that our hypothesis was correct. Our hypothesis is “ Dawn dish soap is the most effective at cleaning due to its widespread popularity, which reflects customer satisfaction, and its superior grease-cutting ability, which is attributed to its unique formulation of surfaces and chemicals.” 

After multiple rounds of testing, we have reached the conclusion that Dawn Platinum dish soap is the most effective at cleaning food off of dishes of the soaps that we tested. The ingredients do have a huge role to play in how dish soap works. Dawn dish soap performed the best because of the surfactant in it. Palmolive, method and ecos don’t have both anionic and nonionic, only anionic, as dawn has both anionic surfactant and nonionic surfactants. Ecos worked the worst, which is the only dish soap with surfactants sodium coco sulfate in it, which may be better for the environment. It did the less effective job at taking away residue and grease. From this observation perhaps sodium coco surfactants don’t work as well because they are plant based.  Anionic are used for their excellent cleaning powers and foaming properties and nonionic are very compatible with other surfactants and are formulated for sensitive skin. Our hypothesis predicted that dawn dish soap would work the best because of the ingredients and the brand's consumer reviews. Our hypothesis was found to be correct because when we were doing the observations there was the least amount of residue on the dawn dishes. Furthermore, the dish soap that received the lowest reviews from consumers also performed the worst in our testing. It is interesting that the consumer reviews showed similar results with our testing which gives us some confidence in trusting these reviews to give independent reviews of the products.  

Finally, we would like to acknowledge that our test is strictly testing the effectiveness of dish soaps in cleaning.  When considering which dish soap to choose, it is also important to understand the impact of the ingredients of the soaps on the environment.  When dish soap goes down the drain, its ingredients still continue to affect the water it is in and it affects the downstreams waterways it returns to.  Some of the chemicals can be harmful to aquatic life and ecosystems.

APPLICATION

We chose to explore the wonders of dish soaps because we always see dish soap ads claiming to be the best dish soap, so we wanted to find out which one really  is the best.

With the information that we have collected, dish soap buyers can now be confident in their spending and  not hesitate on what dish soap brand to buy from. Humans (especially us) often buy products based on brand popularity or viral trends. We believe that this is a big problem nowadays with big companies and how even if their products are not amazing, people are still buying them because of the brand name. We also realized that ads don't need to tell the truth. So could many of the “#1 dish soap claim”’s be fake!  We also found the consumer reviews were fairly accurate in rating the products.

SOURCES OF ERROR

The water temperature may vary slightly because we filled the containers one at a time so the buckets that we filled first might have cooled down a little bit. The water temperature,amount of food on each plate,the amount of soap,the amount of mixing the soap into the water, the same amount of sponge pressure on each plate, and the same amount of time may all vary slightly although we did everything we could to make these tests fair, equal and unbiased.

In addition, we had the same person wipe each plate keeping in mind that each wipe needed to have the same pressure. Since this action was performed by a human there may be some difference in the amount of pressure applied.

CITATIONS

Interview Sources:

Ross Thompson. Colonel Irvine Junior High School. February 24, 2025.

Lai-Wan Chow. Alberta Precision Laboratories. February 16, 2025.

Online Sources:

Forté, C., & Loggins, B. (2024, November 8). 10 best dish soaps for squeaky-clean dishes, according to cleaning experts. Good Housekeeping. https://www.goodhousekeeping.com/home-products/g29209634/best-dish-soaps/

Homecourt.co. (2023, July 25). Biodegradable dish soap: Environmental benefits explained. Retrieved December 5, 2024, from https://homecourt.co/blogs/dish-soap/biodegradable-dish-soap-environmental-benefits-explained

Yeser Chemicals. (2023, April 13). The active ingredients in dishwashing liquid. Yeser Chemicals. Retrieved December 5, 2024, from https://yeserchem.com/the-active-ingredients-in-dishwashing-liquid/

Palmolive. (2025). Palmolive Ultra Strength. Retrieved February 4, 2025, from  https://www.palmolive.com/en-ca/products/liquid-dish-soap/ultra-strength

Dawn. (2025). Dawn Platinum Dishwashing Liquid, Refreshing Rain Scent. Retrieved February 4, 2025, from https://dawn-dish.ca/en-ca/products/dawn-platinum-refreshing-rain-scent/

Method. (2025). Dish soap pink grapefruit. Retrieved February 4, 2025, from https://methodproducts.com/for-your-home/dish/dish-soap-pink-grapefruit-18-fl-oz/

Ecos. (2025). Dish Soap - Grapefruit. Retrieved February 4, 2025, from https://www.ecos.com/dishwashing/dish-soap-grapefruit/

Thank you to our parents for letting us have playdates so we could work on our science project and for buying the supplies we needed to perform the experiments.

Thank you Mr. Thompson for helping us with our project and giving us insightful tips to improve our project. Thank you for opening your room on your lunch breaks and after school. Thank you for organizing this so that our school could participate in it.

Thank you to Lai-Wan Chow - We interviewed Lai-Wan after our first failed experiment. She helped us come up with some ideas to keep the experiment steady. She works at Alberta Laboratory Services so she had lots of good ideas

Thank you to Gia Voth for coming to print out the documents and pictures after school.

Thanks you siblings helping us eat all the food used for this experiment so it wouldn’t be wasted.  There was too much for us to eat by ourselves!