Bubble-ology

Objective

In this experiment you will test if adding glycerin or corn syrup will improve a mixture of bubble solution.

Introduction

Everybody loves bubbles! But what makes bubbles form, and float up in the air until they pop?

A soap bubble (Wikipedia Commons, 2006).

The secret to a good bubble is something called surface tension, an invisible bond that holds water molecules together. Water is a polar molecule, so it has plus and minus ends just like magnets that attract each other. When the water molecules align with each other they stick together, creating surface tension.

You might think that it is the surface tension of the water that holds the skin of a bubble together. Actually, the surface tension of water is too strong to make a bubble. You can try yourself to blow a bubble with plain old water, it just won't work! A good bubble solution has a detergent added to it to relax the surface tension of the water, allowing it to have more elastic, stretchy properties. Now it can act more like the skin of a balloon, stretching out nice and thin, trapping air inside of the bubble like a liquid balloon.

What do you need to make a good bubble solution at home? The basic ingredients are water and detergent. In this experiment, you will add glycerin or corn syrup to see if they can help you make better bubbles. Which solution will make the biggest bubbles? Which bubbles will last the longest?

Terms, Concepts and Questions to Start Background Research

To do this type of experiment you should know what the following terms mean. Have an adult help you search the Internet, or take you to your local library to find out more!

• Water molecule
• Polar molecule
• Surface tension
• Physical properties
• Elastic properties
• Detergent

Questions

• What are the basic ingredients of a bubble solution and what do they do?
• How do the physical properties of the bubbles change when the ingredients change?
• What mixture makes the best bubble solution?

Bibliography

• Read all about bubbles on this website from the Exploratorium Museum in San Francisco, developed by Exploratorium scientist Ron Hipschman:
  Hipschman, R., 1995. "Bubbles," The Exploratorium Museum, San Francisco, CA. [accessed June 6, 2007]
• This article explains the components of a bubble formula and the history of bubbles:
  Pepling, R., 2003. "What's That Stuff? Soap Bubbles," Chemical and Engineering News, Volume 81, Number 17, pp. 34, publication of the American Chemical Society (ACS). [accessed June 6, 2007]
• Read this interesting article about how thin films of water and surface tension are different in space:
  Phillips, T., 2003. "Saturday Morning Science: Elastic Water on the ISS," Science@NASA, Marshal Space Flight Center, National Aeronautics and Space Administration (NASA). [accessed June 6, 2007]
• Here is more information about soap bubbles from Wikipedia:
  Wikipedia contributors, "Soap bubble," Wikipedia, The Free Encyclopedia. [accessed June 6, 2007]

Materials and Equipment

• Glass mason jars with lids (recycled jars work great)
• Measuring cups and spoons
• Distilled Water
• Liquid dishwashing soap (e.g. Dawn®)
• Glycerin, small bottle (available at a drugstore or pharmacy)
• Light corn syrup
• Pipe cleaners
• Permanent marker
• Stopwatch

Experimental Procedure

1. First, make your bubble solutions, and store them in clearly labeled glass mason jars. Use one jar for each different solution and label with the formula using a permanent marker. Here are three basic solutions to try, but notice that the total volume of the solution is kept consistent:

   Ingredient	Solution #1 detergent only	Solution #2 detergent + glycerin	Solution #3 detergent + corn syrup
   Water	1 cup (240 mL) + 1 Tbsp (15 mL)	1 cup (240 mL)	1 cup (240 mL)
   Detergent	2 Tbsp (30 mL)	2 Tbsp (30 mL)	2 Tbsp (30 mL)
   Glycerin	-----	1 Tbsp (15 mL)	-----
   Corn Syrup	-----	-----	1 Tbsp (15 mL)

2. Now make a pipe cleaner wand for each solution. Pinch a pipe cleaner in the middle and give it a kink. Bend one half of the pipe cleaner into a circle and twist together at the center. Repeat with the other two pipe cleaners, and check that all three circles are the same diameter.
3. Go outside and test your bubble solutions. Blow a bubble and catch it on your wand. Immediately start the stopwatch and time how long the bubble lasts. This will take some practice, so try it out on some extra solution before you start!
4. Repeat the experiment as many times as possible for each solution.
5. Record your data in a data table:

   	Solution #1 - Bubble Time (secs)	Solution #2 - Bubble Time (secs)	Solution #3 - Bubble Time (secs)
   Trial 1
   Trial 2
   . . . . . . .
   Trial 20
   TOTAL
   Average Bubble Time in Seconds

6. For each bubble solution, calculate the average time in seconds that the bubbles lasted. Do this calculation by adding up all of the data for a solution, and dividing by the number of trials for that solution.
7. Make a graph of your data. For each solution, make a bar of the average time in seconds that the bubble lasted.
8. Analyze your data. Which formula worked the best?

Variations

• In this experiment, you investigated the presence or absence of an additive like glycerin or corn syrup. What about the concentration? If you are good at timing bubbles, you can try this experiment using different concentrations of glycerin or corn syrup in your solutions. How little is too little, and how much is too much to add?
• Do bubbles always make a spherical shape? Try twisting pipe cleaners into different shapes, like: stars, squares, and triangles. What shape will the bubbles be?
• What happens when three or more bubbles come together? See if you can design an experiment to test the idea that three or more bubbles will always meet at a 120 degree angle.
• Have you ever tried Magic Bubbles? They are bubbles that resist evaporation, and are so stable that you can even touch them without popping. The secret to this formula is that a polymer (an elastic molecule) has been mixed into the solution which adds to the elastic properties of the bubble while helping to prevent evaporation. Try adding your own secret ingredients to your bubble mix. Does it change the physical properties of the bubble? Here are a few suggestions:
  • A small amount of glue, like white glue or gel glue
  • Different combinations of food coloring
  • Some scented oils

Chemistry Project Ideas

Materials and Equipment

• salt
• pepper
• tea kettle
• 2 small glass jars with lids
• water
• measuring cup
• funnel
• coffee filter
• magnifying lens

Experimental Procedure

1. Before you begin, you will want to examine your salt and pepper closely and make some initial observations. Place some salt and pepper on a napkin and using your magnifying glass, make some observations and draw what you see. What do you notice? Record your observations in a data table like the one shown below:
   

   	Salt	Pepper
   Observations before mixing
   Amount before mixing
   Observations of mixture
   Total amount of mixture
   Observations after adding water
   Observations after separation & drying
   Amount after separation & drying

2. In your glass jar, add 1/4 cup of salt, and 1/4 cup of coarsely ground pepper.
3. Put the lid on your jar and shake until the salt and pepper are completely mixed together.
4. Using your magnifying lens, look closely at the mixture. What do you notice? Can you still see the individual grains of salt and pepper? Record your observations in your data table.
5. Put the teakettle on the stove, and heat up some boiling water.
6. Pour 1/2 cup of boiling water into your jar and stir with a spoon. Be careful and get help from a parent or adult, the glass will get very hot!
7. Using your magnifying lens, look closely at your solution. What do you notice? Can you still see the individual grains of salt and pepper? Record your observations in your data table.
8. Place the coffee filter in the funnel and place the funnel in the top of your second glass jar to make your separation apparatus:
   

9. Slowly pour the solution over your filter, being careful not to pour too much at once. As the solution seeps through the filter, let it collect in your jar.
10. Now look at the coffee filter, what do you see? Carefully scrape off any particles with a spoon and place them into the first glass jar.
11. Place both glass jars onto a cookie sheet, and bake in the oven at 325 degrees until all of the water has evaporated from both of the jars. You will need an adults help with this.
12. Remove the jars and allow them to cool to room temperature before handling. They will be very hot!
13. After the jars are cool, use your magnifying lens to make observations of the two jars. What do you notice? Can you still see the individual grains of salt and pepper? Are they mixed together or separated? Record your observations in your data table.
14. Now carefully use a measuring cup to measure the amount of salt and pepper you ended up with. Do these amounts match the amounts you started with? Why do you think this happened?

Variations

• Many different chemicals have different solubilities. By adding different amounts of salt, sugar or baking soda to water you can see how soluble each chemical is. Just add each chemical a teaspoon at a time to a glass of water until you notice that it no longer dissolves when you stir it around. Be sure to use the same amount of water for each experiment! The chemical that dissolves the most into the same amount of water is the most soluble, and the chemical that dissolves that least is the least soluble. Try it!
• How might temperature affect the solubility of a chemical? Try dissolving the same amount of sugar in hot water, room temperature water and ice-cold water. What happens? Can you think of other variables that might affect solubility?

A Soluble Separation Solution

Objective

In this experiment you will learn about soluble and insoluble chemicals, and use the difference in solubility of salt and pepper to separate the components of a mixture.

Introduction

Chemistry is the study of matter and how matter behaves and interacts with other kinds of matter. The way that matter behaves is called a "property" of matter. Everything around us is made of matter, and you can explore the properties of matter using some common chemicals around your home.

One important property of matter is called "solubility." We think about solubility when we dissolve something in water. If a chemical is soluble in water, then when you add it to water it will dissolve, or disappear. If it is not soluble, then it will not dissolve and you will still see it floating around in the water.

When you add a soluble chemical to dissolve in water you are making a "solution," and solutions are very important for chemistry. We call the chemical you are adding the "solute" and the liquid that it dissolves in the "solvent." Even though after a solute dissolves in a solvent it becomes invisible, it is still there. If you were to evaporate all of the liquid away from the solution, you would be left with your dry chemical again. In fact, this is how salt is processed in giant salt flats where seawater is slowly evaporated, leaving behind huge amounts of sea salt.

All of the different kinds of matter can be sorted into categories based upon whether they are soluble or not in different solvents. Because of this, the properties and solubility of different chemicals can be used to separate mixtures of chemicals. A chemical mixture is a blend of two or more different kinds of chemicals where the individual chemicals do not react with each other, but remain separate. You can see an example of this when you look closely at a dry mixture of salt and pepper.

In this experiment, you will use the different properties of the chemicals in salt and pepper to separate a mixture. By doing this, you will learn about the solubility of soluble and insoluble chemicals.

Terms, Concepts and Questions to Start Background Research

To do this type of experiment you should know what the following terms mean. Have an adult help you search the internet, or take you to your local library to find out more!

• chemical
• crystals
• mixture
• solution
• soluble
• solute
• solvent
• insoluble
• filtration
• evaporation

Chemistry Science Fair Project Ideas

An experienced chemistry professor used to say that it took about one explosion per week to maintain college students' attention in chemistry lectures. At that rate, we'd get in pretty big trouble with a lot of moms and dads, but we still have a lot of interesting science fair project ideas that involve chemistry—without the explosions.