Compare two dish washing liquids to see which one makes more bubbles.

Introduction:

You can make bubbles by blowing air in a liquid detergent. White foam generated while washing dishes are also made of millions of small bubbles. Bubbles and foams often show the quality of a detergent and it’s active material.
Making bubbles is fun and a hubby for some people, but washing machines usually don’t like much bubble. Manufacturers of detergents produce a special quality detergent for washing machines that creates less bubbles.

Information Gathering:

The following links are all about bubbles. Although they are not directly related to this project, it is good to look at them. They can show you that bubbles have some serious science

• Bubble Geometry
• Bubble Sphere
• Anti bubbles
• Soap bubbles

Question/ Purpose:

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.
What detergent makes more bubbles? What factors affect the amount of bubble.

Identify Variables:

When you think you know what variables may be involved, think about ways to change one at a time. If you change more than one at a time, you will not know what variable is causing your observation. Sometimes variables are linked and work together to cause something. At first, try to choose variables that you think act independently of each other.

Independent variable (also known as manipulated variable) is the type or brand of detergent. Possible values are Dawn, Joy, Ajax.

Dependent variable is the amount of bubbles. It will be measured by measuring the height of bubbles in a bottle.

Controlled variables are temperature, moisture and concentration of detergent can possibly affect the amount of bubbles.

Constants are the type and size of test bottles, amount of air blown into detergents.

Hypothesis:

Based on your gathered information, make an educated guess about what types of things affect the system you are working with. Identifying variables is necessary before you can make a hypothesis. One possible hypothesis is as follows:

The expensive detergent will create more bubbles. Also detergents will create more bubbles before dilution.

Experiment Design:

Design an experiment to test each hypothesis. Make a step-by-step list of what you will do to answer each question. This list is called an experimental procedure. For an experiment to give answers you can trust, it must have a “control.” A control is an additional experimental trial or run. It is a separate experiment, done exactly like the others. The only difference is that no experimental variables are changed. A control is a neutral “reference point” for comparison that allows you to see what changing a variable does by comparing it to not changing anything. Dependable controls are sometimes very hard to develop. They can be the hardest part of a project. Without a control you cannot be sure that changing the variable causes your observations. A series of experiments that includes a control is called a “controlled experiment.”

Experiment:

Introduction: For this experiment we get two different detergent samples (two different brands) that also have two different prices. We will initially compare two detergent samples with their original concentration and identical conditions (Same temperature).
We may also repeat the same experiment with different dilutions of the same detergents.

Procedure:

Get two empty 2 liter soda bottle and make sure that they are both clean and dry.
Label the bottles with the names of detergents that you are going to test.
(To make it simple, we are using numbers instead of names)
Add one cup of detergent number 1 in bottle number one and one cup of detergent number 2 in the bottle number 2.

Now we need to use a long straw and blow air in detergent that are at the bottom of soda bottles. To make sure that the same amount of air is used for both bottles, get two identical balloons. Blow the balloons until they are the same size. Now use the long straw and slowly transfer the air from balloons to detergents. It is good if you do this test when you have a helper. In this way you can start and stop blowing at the same time. After the test, mark the level of bubbles in the soda bottle and compare them.

You can repeat the same experiment a few times and compare the results.

Also make a diluted 50% solution (Half water, half detergent) of both detergents and repeat the test with diluted sample.

Make a graph:

Make a bar graph to show the results of your experiment. Each bar will be for one of the detergents that you are testing. Write the name of that detergent below the bar. The height of the bar will be the height of bubbles.

If you are testing different solutions of detergent, you may want to make a separate bar for each solution. For example you will have detergent 1, detergent 2, 50% detergent 1, 50% detergent 2.

Materials and Equipment:

1. Water
2. Two different detergents
3. Two soda bottles
4. Two long straws (or you can connect 2 regular straw to make a long one)
5. Two latex balloons

Results of Experiment (Observation):

Record the results here

Calculations:

If you need help with any calculation, contact your project advisor.

Summary of Results:

Summarize what happened. This can be in the form of a table of processed numerical data, or graphs. It could also be a written statement of what occurred during experiments.

It is from calculations using recorded data that tables and graphs are made. Studying tables and graphs, we can see trends that tell us how different variables cause our observations. Based on these trends, we can draw conclusions about the system under study. These conclusions help us confirm or deny our original hypothesis. Often, mathematical equations can be made from graphs. These equations allow us to predict how a change will affect the system without the need to do additional experiments. Advanced levels of experimental science rely heavily on graphical and mathematical analysis of data. At this level, science becomes even more interesting and powerful.

Conclusion:

Using the trends in your experimental data and your experimental observations, try to answer your original questions. Is your hypothesis correct? Now is the time to pull together what happened, and assess the experiments you did.
The results of my experiment showed that ….

Related Questions & Answers:

• If your experiment answered any other questions that you might have had in your mind, state them here.

Possible Errors:

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.

References:

You will need some books, other publications and websites for your bibliography. Visit your local library and find books about soaps and detergents. Include such books in your bibliography.
For online resources you may review the following link and the related links it contains:

http://en.wikipedia.org/wiki/Detergent

A similar project is:

which dishwashing liquid cleans the most dishes?

In this project you must compare two different dish washing liquid to determine which one can clean more dishes. The main function of a dish washing liquid in cleaning dishes is dissolving oils and fats. So this question can be changed to a more technical form like this:

Which dishwashing liquid dissolves most oil?

Gathering information:

While gathering information you will study books related to soap and detergents. Such studies will show you the the molecules of soaps and detergents have two ends. One end is the polar end that bounds to water. The other end is the non-polar end that binds with oil molecules. Such two end molecules allow oils to dissolve in water. As a result we can used them to wash oily dishes.

Variables:

Independent variable is the brand of detergent (joy, dawn,…)

Dependent variable is the rate in which a detergent can dissolve oil. (In other words you want to see how much oil can be dissolved using each gram of detergent.)

Controlled variables are temperature, amount of water, procedures and type of oil.

Hypothesis:

As your hypothesis write which detergent do you think will dissolve more oil. Also write why do you think so.

Experiment:

In this experiment you compare two detergents for their ability to dissolve oil at room temperature.

Procedure:

Leave your detergent samples and water in the room for about 2 hours. This will allow water and detergents to become room temperature.

For each of the detergents that you are testing get a test tube and label them with the name of detergent. (You may also use a graduated cylinder instead of test tube.)

In each test tube add 10 ml water (you may use a pipette to do that)

In each test tube add 1 ml of detergent. (the same detergent labeled on the test tube).

With your tomb close the test tube and slowly turn it upside town. Hold it for a second and turn it back to right side up. Repeat this a few times until the detergent mixes with water without creating much foam. Now you will have a solution of detergent in water.

In each test tube add 5 ml liquid oil. Initially oil stays on the top. Continue mixing as you did in the previous step exactly 10 times. An oil emulsion will be formed.

Leave the test tubes in the test tube holder and make observations after 2 hours. Record the levels of separation. After separation you will have a layer of water at the bottom, a layer of oil on the top and a layer of emulsion in between. For a better detergent you will have a larger layer of emulsion and smaller layer of oil on the top.

Record your results in a table like this

*In a good detergent, the height of oil layer will be 0 (zero

*More emulsion represents a better detergent.