Science project

Which Detergent Extracts Strawberry DNA The Best?

While conducting my experiment, I completed ten trials for each type of detergent. The additional trials were completed to reduce error in my results. I utilized a graduated test tube to measure the amount of visible extracted DNA. The measurements confirmed my hypothesis that Ajax dishwashing liquid extracted the most visible DNA.

Life Science
6th Grade
Difficulty of the Project
Safety Issues
Time Taken to Complete the Project
2 months

The purpose of the experiment is to test the effectiveness of a dishwashing liquid, a laundry detergent, and a shampoo during a DNA extraction process from a strawberry.

  • Three 250 ml tri-pour beakers
  • One glass extraction rod
  • One plastic 4 oz squeezing bottle
  • 10 graduated test tubes
  • 91% isopropyl alcohol
  • Blue monster DNA stain
  • Powder buffer (which contains)-
    • DNA suspension agent
    • pH stabilizer
    • Protein destroyer
  • Nylon fast flow filter
  • Measuring spoons
  • Thermometer
  • 4 pipettes
  • Purex laundry detergent
  • Fructis shampoo
  • Ajax dishwashing liquid
  •  Test Tube Holder
  • Strawberries
  • Blender
  • 3 Bowls
  • Distilled water

Deoxyribonucleic acid, also abbreviated as DNA, is the substance in the cells of living things that contains the information of life (Wilcox, 8). Among animals, plants, and microorganisms, there are many kinds of cells that have different shapes and perform different functions (Ruiz, 12). Plant and animal cells are eukaryotic cells, which mean that the nucleus is isolated from the cytoplasm by a membrane called the nuclear membrane (20). The DNA is located inside the nucleus. 

When a person is eating a strawberry, they do not realize they are eating strawberry DNA! A strawberry is an octoploid which means has eight sets of seven chromosomes makes its genetics very complex. Scientists are therefore working on wild diploid strawberries which are easier to analyze, and then seek to apply knowledge across to the cultivated strawberry.

Buffer A solution that protects or “buffers” a reaction against changes in pH.

DNA - Deoxyribonucleic Acid, the substance of inheritance, which directs the growth, organization, development, and function of cells.

I predict that the use of Ajax dishwashing liquid will be the best at breaking down the cell membrane and allow the greatest amount of DNA to become visible. I believe this because I have observed the way dishwashing liquid breaks down the grease on pots and pans while cleaning the dishes.

To perform my experiment I completed the following steps:

  1. Add 4 oz of distilled water to the beaker
  2. Add 1 ¼ oz (6.25 ml) of powdered buffer into the beaker
  3. Stir until buffer is dissolved in distilled water
  4. Add 5 ml of detergent to mixture, and stir for 2- 4 minutes, slowly (Try not to create suds)
  5. Put mixture into ice and chill
  6. Mash 5 strawberries in a blender
  7. Warm up a cup of hot water at 60 degrees Celsius
  8. Put “mush bag” into water
  9. Set it in hot water for 10 minutes
  10. Put 5 tbsp (75 ml) of mush into a beaker
  11. Put 10 tbsp of chilled buffer into beaker
  12. Stir mush with chilled buffer for 4 minutes
  13. Pour the mush into the beaker with the filter
  14. Add 5 ml of “liquid from mush” into each of ten test tubes
  15. Add 5 more ml of alcohol to test tubes
  16. Put 1 drop of Blue DNA Stain into each beaker
  17. Observe white, slimy DNA
  18. Measure your results

During my experiment the following made up my controls:

  1. Strawberries
  2. Distilled water
  3. Powdered Buffer

The following was my variable:

  1. Type of detergent

I performed the following three sets of experiments 10 times:

  1. DNA extraction with Ajax dishwashing liquid
  2. DNA extraction with Purex laundry detergent
  3. DNA extraction with Fructis shampoo

The ten Ajax experiment trials resulted in measured extractable DNA from 0.250 to 1.500 milliliters with an average extracted DNA of 0.775 milliliters. The use of Ajax produced the most consistent results. Six of the ten trials produced 0.750 milliliters of visible DNA. 

The ten Purex experiment trials resulted in measured extractable DNA from 0.250 to 1.750 milliliters with an average extracted DNA of 0.625 milliliters. Out of all 30 trials for all three detergents, one of the Purex trials had the highest amount of visible DNA, which was 1.750 milliliters. Even though Purex produced one of the largest quantities of visible DNA in one trial, the remaining nine trials did not produce consistent results. 

The ten Fructis experiment trials resulted in measured extractable DNA from 0.100 ml to 1.500 milliliters with an average extracted DNA of 0.485 milliliters. Two of the Fructis trials had the lowest amount of visible DNA, which was 0.100 milliliters. The Fructis trials produced the same inconsistencies similar to the Purex trials.


Trial #




Avg DNA ml

At the conclusion of the experimental trials, I found that my hypothesis was correct. I had predicted that Ajax dishwashing liquid would produce the most extractable DNA. The measured results showed that Ajax produced almost two times more DNA than Fructis Shampoo and had the most consistent results for each trial. The thirty separate trials went smoothly and I had no problems

.An interesting future experiment might involve changing the stage of ripeness, using different temperatures, or levels of sun exposure. Another study could involve the use of different types of fruits and vegetables. This experiment taught me that every human and plant cell contains DNA.


“DNA Is Like A Library Of Instructions”

Copyright 2011

Accessed 2/10/11


2. “How Is DNA Extracted and Examined?”

Tyler Lacoma

Copyright 2011

Accessed 1/18/11



“Methods of DNA Extraction in Plants”

Ma Wen Jie

Copyright 2011

Accessed 1/18/11



Eukaryotes= Animal and Plant Cells

Nigel D. Purchon

Copyright 2000

Accessed 1/18/11



“Strawberry Processing Techniques: Freezing and Freeze-Drying”

Dr. Harmit Singh

Copyright 2005

Accessed 1/18/11



“Strawberry Plant Scientific Classification”

Copyright 2011

Accessed 1/18/11


7. Illustrated Science Encyclopedia

“DNA” and “Detergent”

Raintree Steck-Vaushn

Volume C

Copyright 1997

Volume 6

Pg 538


8. DNA The Thread of Life

Frank H. Wilcox

Copyright 1988

Lerner Publications Company


9. Genetics

Lynette Brent Sandvold

Copyright 2010


New York


10. Genetic Engineering

Clarice Swisher

Copyright 1996

Lucent Books, Inc.


11. Life Lines: The Story of New Genetics

J. S. Kidd and Renee A. Kidd

Copyright 1999

Facts On File, Inc.

New York


12. The Life of a Cell

Andres Llamas Ruiz

Copyright 1997

Sterling Publishing Co., Inc.

New York


13. DNA: The Ladder of Life

Edward Frankel

Copyright 1979

McGraw-Hill Book Company

New York

Author: Mary T.
Disclaimer and Safety Precautions provides the Science Fair Project Ideas for informational purposes only. does not make any guarantee or representation regarding the Science Fair Project Ideas and is not responsible or liable for any loss or damage, directly or indirectly, caused by your use of such information. By accessing the Science Fair Project Ideas, you waive and renounce any claims against that arise thereof. In addition, your access to's website and Science Fair Project Ideas is covered by's Privacy Policy and site Terms of Use, which include limitations on's liability.

Warning is hereby given that not all Project Ideas are appropriate for all individuals or in all circumstances. Implementation of any Science Project Idea should be undertaken only in appropriate settings and with appropriate parental or other supervision. Reading and following the safety precautions of all materials used in a project is the sole responsibility of each individual. For further information, consult your state's handbook of Science Safety.

Add to collection

Create new collection

Create new collection

New Collection


New Collection>

0 items

How likely are you to recommend to your friends and colleagues?

Not at all likely
Extremely likely

What could we do to improve

Please note: Use the Contact Us link at the bottom of our website for account-specific questions or issues.

What would make you love

What is your favorite part about