Laundry Detergent Comparison Science Project

Hypothesis, Materials, Constants, and Variables

young girl conducting a Science project in a beaker

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Laundry is the inevitable result of being clothed. Science projects are the inevitable results of having kids in school. Finding a topic for a science project is almost more difficult than doing the project. Why not do a laundry detergent comparison project? These guidelines can be adapted for younger children or high school science projects.

This guideline can be used to compare:

  • Which brand of detergent removes specific stains more effectively
  • Homemade detergent vs commercial brand detergent
  • Plant-based laundry detergent vs petrochemical-based laundry detergent
  • Enzyme enhanced detergent vs non-enzyme detergent (Higher priced detergent vs inexpensive detergent)

The same process could also be used to compare the effect of different types of bleach on a variety of fabrics—chlorine bleach vs hydrogen peroxide vs oxygen-based bleach.

Start With Research

Before launching any science project, research should be done to give the student a working knowledge before any testing comparisons begin. For this project, it is important to learn the components of laundry detergent and how they function in removing soil and stains. While almost all detergent labels feature information on product ingredients, some do not include a complete listing. However, the complete product ingredient list, as well as Material Safety Data Sheets, can be gathered by calling the product's consumer helpline or visiting the manufacturer's website.

If the experiment is to test homemade laundry products, gather formulas for both liquid and powdered detergents. Make a list of needed ingredients to make these detergents for the project.

It is also important to understand the components of stains and how different ingredients in detergent affect each type of stain. Stains can be divided into protein-based, oil-based, tannin-based, dye-based and combination stains.

Gathering this background research will help develop the hypothesis and determine the experiment that you want to conduct.

State the Hypothesis

The hypothesis is a statement or prediction made based on limited scientific evidence but as a starting point for further investigation. The hypothesis should be based on reasoning but without any assumption of its truth. The conducted experiment will determine whether the hypothesis is true or false.

Examples of hypotheses for laundry detergent science project:

  • Laundry detergents that contain enzymes will remove stains more effectively than those detergents that do not contain enzymes.
  • Homemade laundry detergents will remove stains more effectively than commercially-based detergents.
  • Plant-based laundry detergents will remove stains more effectively than petrochemical-based laundry detergents.

Gather Experiment Components

The experiment is the vehicle to test the hypothesis. It is critical to develop a list of materials, constants, and variables.

Test fabric: Unless you are testing how a laundry detergent(s) remove stains from different types of fabric, each test square should be identical in fabric type, size, and weight. It is important to know the fiber content of the squares—100-percent cotton is standard. To achieve the best data for analysis, have multiple test squares for each step of your experiment. Be sure to keep several unstained squares to use for base comparison.

Laundry products: Gather all of the products you will be using before you begin the experiment to reduce variables if you have to delay a process to run to the store.

Labels: Each test square should be labeled with a permanent ink marker so that there is no confusion within the data.

Measuring tools: Precise measuring is important for both the materials used for staining and the detergent product used. Standard measuring cups and spoons are essential.

Thermometer: Water temperature is a variable that can be controlled by ensuring that each test square is washed at the same temperature.

Staining material: Whether you are using ketchup, oil, strawberries or powdered soft drinks (Kool-Aid) to stain the test square, be sure to use the same brand and the same amount on each test.

Establish the constants for your experiment: test squares, staining material, water temperature, amount of detergent, the cleaning method, drying method

Establish variables: different detergents used or different types of stains or different washing methods

Collect Data

Before beginning the experiment, determine the data you plan to collect. By having a baseline test square of fabric, you can more easily rate which detergent cleaned more efficiently. It will help to have a microscope or magnifying glass to observe how much stain is still left in the fabric after washing.

Analyze the Data

Before you draw a conclusion, the data should be analyzed. You can use statistics to determine if there is a stronger relationship between certain types of detergents and stain removal than there is between other types.