Laundry Detergent Comparison Science Project

Doing a comparison of different laundry detergents can make for an interesting and informative science fair project. There are many different factors to consider when selecting the right detergent for your laundry needs. In this article, we will explore some of the key considerations when comparing detergents, and provide guidance on designing an experiment to test different brands and formulations.

Overview of Laundry Detergents

Laundry detergents work by suspending dirt, oils, and other grime from your clothes and linens in water, so they can be rinsed away. They contain surfactants, which are compounds that lower the surface tension of water, helping it penetrate fabric fibers more effectively. The main types of surfactants used are:

  • Anionic surfactants – Negatively charged. Most common type used. Good at removing oils and dirt. Examples are sodium lauryl sulfate and sodium laureth sulfate.
  • Nonionic surfactants – Not electrically charged. Gentler on skin. Used in liquid detergents. Examples are alcohol ethoxylates and glycol ethers.
  • Cationic surfactants – Positively charged. Used in fabric softeners and dryer sheets. Examples are distearyldimonium chloride and cetrimonium chloride.

In addition to surfactants, laundry detergents contain builders, which help remove mineral deposits from water that can interfere with cleaning. Common builders are phosphates, carbonates, silicates, and zeolites.

Some other ingredients found in detergents include:

  • Bleaches – Remove stains by oxidizing and whitening fabrics. Examples are sodium hypochlorite, hydrogen peroxide, and sodium perborate.
  • Enzymes – Break down protein, starch, and fat-based stains. Examples are protease, amylase, and lipase.
  • Optical brighteners – Absorb ultraviolet light and emit blue light to make clothes appear whiter. Examples are stilbene and coumarin derivatives.
  • Fragrances – Provide pleasant scents. Can be natural or synthetic compounds.
  • Dyes – Add color to liquid detergents. Examples are acid and basic dyes.

When designing an experiment comparing laundry detergents, some key factors to consider are:

Effectiveness at Stain Removal

One of the main purposes of laundry detergent is to remove tough stains from fabrics. Testing how well different formulations remove standard stain types like grease, blood, grass, wine, etc. can provide useful information about their cleaning ability.

You can create stained swatches using common staining agents, then launder them using each detergent and compare the results. Some examples of stains to create include:

  • Oil/grease – Used motor oil, butter, bacon grease
  • Pigment – Grass, mud, makeup
  • Protein – Blood, egg, meat juice
  • Carbohydrate – Syrup, soda, ketchup

Make sure to use the same fabric type for each swatch, like plain cotton cotton or polyester. White fabrics work best to assess stain removal. Swatches should be stained in advance and dried fully before washing.

Effectiveness in Different Water Temperatures

Water temperature plays a major role in activating the cleaning agents in laundry detergent. Testing stain removal in cold, warm, and hot water can demonstrate the optimal temperature for each product.

Detergents that perform well in cold water can save energy by allowing lower temperature washes. Enzyme-based detergents often do better in cooler water compared to those relying more on alkaline builders that require hot water to work best.

Amount of Residue Left Behind

Detergents that do not rinse away fully can leave residue on clothes that leads to dinginess over time. This is evaluated by testing washed fabric swatches for any visible coating or discoloration.

Swatches can be immersed in distilled water, then evaluated to see if the rinse water becomes cloudy, indicating residual detergent. The pH of the rinse water can also be tested, with values above 7 indicating alkaline residue.

Effect on Fabric Color Fading

Laundry detergents that contain bleaching agents can cause fading of fabric dyes over repeated washing. This is tested by washing swatches of colored fabrics and evaluating color change compared to an unwashed control.

Sensitive, brightly colored fabrics are especially at risk of fading. Red and black fabrics tend to show fading most clearly. The degree of color loss indicates the harshness of the detergent.

Fragrance Intensity and Persistence

Fragrance is a major consideration for laundry detergent consumers. The intensity and longevity of each product’s scent can be evaluated by trained panelists or consumer groups.

Ratings can be gathered on initial fragrance strength, how long the scent persists on laundered fabrics, and any changes in intensity or quality over time. Consumer preferences for fragrance can vary greatly.

Effect on Fabric Softness

Some detergents contain conditioning agents, waxes, or silicones to impart fabric softening during washing. The soft handfeel of laundered fabrics can be judged by trained panelists touching and ranking the fabrics.

Detergents with softeners built in may reduce the need for separate fabric softener in the wash cycle. Softness ratings can indicate if any formulations cause fabric stiffness or roughness.

Foaming and Lathering Ability

Consumers often associate foaming and lather with cleaning ability, although high foam levels do not necessarily indicate better stain removal. Comparing the foam produced by each detergent still provides useful data.

Agitating swatches in detergent solutions and evaluating bubbles visually or by volume can allow foaminess ratings. Stability of lather over the wash cycle is also important.

Packaging and Label Information

Packaging, pricing, and label information should be noted for each detergent tested. Important details include:

  • Formulation (powder, liquid, tablet, pod, etc.)
  • Volume and number of loads
  • Price per load
  • Manufacturer claims of performance benefits
  • Instructions for optimal dosage and water temperature

Experiment Design

A well-designed experiment allows for controlled testing of multiple laundry detergents across the parameters discussed above. Here are some guidelines for setting up an effective experiment:

1. Choose 3-5 Detergent Brands

Select 2-3 mainstream national brands along with 1-2 specialty or green detergents. Try to vary the detergent forms – test both liquids and powders.

2. Obtain Standard Fabric Swatches

Use white cotton and a colored fabric like red cotton or black polyester. Cut swatches into 4 x 4 inch squares, with 3-5 replicates for each stain and test.

3. Create Stained Swatches

Prepare a set of swatches for each stain type. Vary staining agents – try butter,motor oil, ketchup, blood, grass, etc. Apply similar amounts of stain to each swatch.

4. Wash with Varying Temperatures

Divide stained swatches into sets and wash in cold, warm, and hot water. Use recommended dosages and cycle lengths.

5. Evaluate and Rate Performance

Rate stain removal on a 4-point scale. Judge residue, fading, softness, and foaming. Photograph swatches for comparison.

6. Compile and Analyze Results

Organize results into tables. Calculate averages for each detergent and parameter tested. Perform statistical analysis if possible.

7. Draw Conclusions

Determine if differences between detergents are statistically significant. Identify strengths and weaknesses of each formula based on ratings. Suggest improvements.

Experiment Variations

There are many possible ways to modify and expand on a basic laundry detergent comparison. Some additional variables to test include:

  • Vary detergent dosage – try both underdosing and overdosing.
  • Test on different fabric types – cotton, polyester, wool, silk.
  • Wash in soft vs. hard water – use distilled vs. tap water.
  • Add bleach to some detergent tests.
  • Wash in warm or hot water, then rinse in cold.
  • Test “green” detergents containing natural ingredients vs. conventional.
  • Compare scented and unscented versions of the same detergent.
  • Look at stain removal over multiple wash cycles instead of just 1.
  • Compare detergent efficacy in standard vs. high efficiency washing machines.
  • Examine laundered fabrics under blacklight to detect optical brighteners.

Benefits of the Laundry Detergent Comparison Project

Beyond learning about chemistry and consumer products, creating an experiment to compare laundry detergents has numerous benefits for student researchers:

Gains Practical Life Skills

Doing laundry is an essential life skill that students will need to master as they become more independent. Understanding how to select and use the most effective detergents helps build real-world knowledge.

Provides Consumer Education

The project highlights how to be a smart, informed consumer when faced with a whole aisle of detergent choices at the supermarket. Students learn to think critically about marketing claims.

Teaches Scientific Method

Formulating a hypothesis, systematic testing, collecting data, analyzing results, and drawing conclusions are all integral parts of the scientific method that students will hone through this project.

Allows Creativity

Students can employ creativity in designing their experimental parameters, choice of stain types, methods for evaluating results, expanding the project scope, and presenting their findings.

Utilizes Math/Analytics

Calculating averages, making graphs, and doing statistical analysis of results allow students to develop and apply key math skills while engaged in a hands-on science project.

Provides Life Relevance

Cleaning clothes is an essential chore most people face their whole lives. Gaining deeper understanding of laundry products provides useful, real-world scientific knowledge.

Sparks Passion for Science

Hands-on experiments comparing recognizable products can help make science come alive for students. It provides an engaging way to learn scientific concepts.

Builds Confidence

Successfully designing and carrying out an experiment from start to finish, then presenting the results, allows students to gain confidence in their scientific abilities.

Fosters Independence

Science fairs allow students to take ownership of a project with minimal input from parents and teachers. They make independent choices to reach conclusions.

Prepares for Future Education

The skills developed in creating science fair projects provide a strong foundation for continuing science education in high school and college.

Designing the Laundry Detergent Comparison Display

An excellent laundry detergent experiment still needs an engaging display board to really shine at a science fair. Here are some tips for creating displays that complement your project:

Organize Content Logically

Lay out your display in a logical flow moving from hypothesis to experiment setup to results/conclusions. Group related content together in sections.

Use Headings and Bullets

Break up large blocks of text by using bullet points, headings, charts, and photos. Aim for a mix of text, graphics, and blank space.

Emphasize Photos

Show your stained swatches and highlight differences seen after washing. Photos of your experiment in progress also help tell the story.

Make Graphs and Charts

Visually depicting your data makes it more understandable. Bar charts, tables, and line graphs help viewers grasp the results.

Credit Sources

Cite any outside sources used for background information with a small bibliography section. Give credit to sites used for images.

Pick a Color Scheme

Use coordinating colors for headings, backgrounds, and graphics. Keep it simple with 1-2 colors. Avoid loud neon colors.

Highlight Key Facts

Call out especially interesting or surprising findings with pull quotes and text boxes. Draw viewers in to look closer.

Choose Appropriate Fonts

Stick to basic, easy to read fonts like Arial, Calibri, and Helvetica for large text. Use italics and bolding for emphasis.

Check for Errors

Carefully proofread all text, data, and graphics before finalizing. Double check that your conclusion accurately reflects the data.

Practice Your Presentation

Be prepared to explain your project, findings, and any future research goals. Practice speaking clearly and confidently.

Frequently Asked Questions About the Laundry Detergent Comparison Project

Q: How many laundry detergents should be tested?

A: 3-5 detergents is ideal. Test 2-3 major national brands and 1-2 specialty or green detergents. Comparing a mix of liquids, powders, and pods works well.

Q: What are some good stains to use?

A: Try to select stain types representing carbohydrates, fats, proteins, and pigments. Ketchup, grass, blood, oil, wine, chocolate, and makeup work well.

Q: What temperature water should be used?

A: Test stain removal in cold, warm, and hot water if possible. Follow detergent label instructions for recommended temperatures.

Q: How many stained fabric swatches are needed?

A: Prepare 3-5 identical swatches for each stain type to allow testing in different water temperatures and repetitions.

Q: How should stained swatches be evaluated?

A: Use a 4 point scale to rate stain removal. Also note fabric damage, residue, and fading. Take photos before and after washing.

Q: What statistical analysis can be used?

A: Compare means and standard deviations between detergents. Analysis of variance (ANOVA) can identify significant differences if sample sizes are large enough.

Q: How long should the experiment take?

A: Plan at least 1-2 months for background research, procuring materials, testing, and analysis. Actual washing can be done over a weekend.

Q: What should the display board focus on?

A: Emphasize photos of stained swatches before and after washing along with charts/graphs of your results and findings.

Q: Is a control needed for comparison?

A: Washing some swatches with just water provides a control to represent the effect of the water temperature alone.


Comparing laundry detergent effectiveness makes for a compelling science fair project that is also highly practical. Students can utilize the scientific method meaningfully while also exploring real-world consumer product testing. Visual stain removal results combined with quantitative data analysis allows young scientists to draw solid conclusions. Displaying the experiment and findings clearly then teaches effective science communication skills. With so many different detergent options available now, learning what works best on different stains and fabrics gives students valuable knowledge that they can apply in their own laundry for years to come.