Introduction: (Initial Observation)
Almost all manufacturers of detergents claim that their products can clean better. What is the fact? Which one really cleans best? Some buyers compare the price and simply buy the more expensive one assuming that there must be a good reason for price difference. Those who are more price conscious may choose the cheapest one assuming that they are all the same.
In this project you will compare three (or more) different detergents for their ability to remove organic stain. Here we focus on organic stain because organic stain is the most common form of stain. Organic stains are stains from plants or animal sources such as stains from foods and fruits.
For each detergent that you choose to test see if there is a home-page on the web and find any information the producer provides about that specific detergent. Also search the web for the term “detergents” and related terms to gain useful information about detergents.
Visit your local library and find books about soaps and detergents. Get an idea of what material is used in making detergents.
What do you want to find out? Write a statement that describes what you want to do. Use your observations and questions to write the statement.
The purpose of this project is to find out which detergent is more effective on removing organic stain.
Which detergent removes the organic stain the best?
Detergents are available in different brands and with different prices. We are not sure if the more expensive detergents are really better. The problem is that we may be paying more for detergents that are not more effective.
The independent variable is the type of detergent
The dependent variable is the time it takes for a certain solution of detergent to completely remove the stain
Controlled variables are:
- Concentration of detergent (ratio of detergent to water)
- method, procedures and water
- Original form of detergent (liquid, powder)
- stain type
You will state which detergents have been selected and then the hypothesis will state which of the detergents is believed to be more effective. The hypothesis may be based on your intuition or past experiences with detergents.
Materials Needed are:
- Samples of 3 different detergents
- 3 bowls or beakers
- 3 spoons or wood dowels for stirring
- Ink, fruit juice or any other staining liquid
- 3 pieces of white cotton fabric about 10 cm x 10 cm each
- Pipette or eye dropper
- Place 10 grams (or one spoon) of the detergent in each beaker or bowl.
- Label the beakers with the name of detergent that you are testing.
- Add one liter of warm water to each bowl.
- Place one drop of stain in the center of each fabric.
- Wait for 60 seconds so the stain will fixate itself on fabric.
- Record the time and insert all three fabrics in the detergents.
- Stir all three detergents slowly. If you have no help, stir each one for two seconds and go to the next one and repeat the cycle.
- Record the time and the name of detergent as soon as any of the fabrics completely loses the stain. Your results table will look like this:
Time it took for detergents to remove …. stain
|Name of detergent
|Time it took to remove the stain
Use the above results table to draw a bar graph. Each bar is for one detergent. The height of each bar can be the time (number of minutes) it took to remove the stain.
This graph shows how slow the detergents are in removing a specific stain. Most people like to know how fast the detergents are in removing the stain. To do that simply reverse the numbers and call them the cleaning speed. For example, if one detergent removes the stain in 8 minutes, it means that each minute, it removed 1/8th of the stain. Your new results table may look like this:
Rate of stain removing in different detergents
|Name of detergent
|Rate of stain removed per minute
If you use this table to draw a graph, the results are much meaningful because the taller bar represents a better detergent.
Fine tune your experiment: You may have chosen a stain that all detergents can remove it in a few seconds. Then it will be hard to do the experiment and record good results. If this happened to you, select a different stain or let the stain dry and then try. You may even change the concentration of detergents.
Results of Experiment (Observation):
The data could be presented in written form or a bar graph would be an excellent visual method of displaying the final results. Each brand tested should have its own bar. The length of the bars would be proportional to the percent of stain removed or percent of stain that remained.
Summary of Results:
All measurements should be recorded in the project book and may be presented in the final project report either as numerical data or shown as a bar graph. For each brand of detergent tested, the length of the bar should show the percentage of stain removed.
The conclusion to the report will state the ranking of the various detergents, and decide if the original hypothesis was proved or disproved. The conclusions might also state any relationships you have noted between the popularity of a given detergent and its effectiveness or its price.
Related Questions & Answers:
What you have learned may allow you to answer other questions. Many questions are related. Several new questions may have occurred to you while doing experiments. You may now be able to understand or verify things that you discovered when gathering information for the project. Questions lead to more questions, which lead to additional hypothesis that need to be tested.
If you did not observe anything different than what happened with your control, the variable you changed may not affect the system you are investigating. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. The first thing to check is how you are making your measurements. Is the measurement method questionable or unreliable? Maybe you are reading a scale incorrectly, or maybe the measuring instrument is working erratically.
If you determine that experimental errors are influencing your results, carefully rethink the design of your experiments. Review each step of the procedure to find sources of potential errors. If possible, have a scientist review the procedure with you. Sometimes the designer of an experiment can miss the obvious.
Your references are this website and the books that you will find in your local library about detergents. You can also include the websites of detergent manufacturers and some of the following: