The Best of Bubbles

Introduction:

Bubbles are naturally fun and fascinating. In fact, bubble solution is routinely the best selling toy item in the United States and over 50 million containers of it are sold each year. Some people get so attached to bubbles that they become expert "bubble-ologists" who perform at county fairs and bubble festivals.   But aside from being good clean fun, their unusual behavior also illustrates a range of important science concepts that can be investigated by kids through a variety of simple explorations. 

Purpose: Your task in this exploration is  to explore the unusual behavior of bubbles through a variety of activities.

Materials:  

Bubble Solution - (store bought brands like Mr. Bubble work very well)

Homemade version: mix one cup Dawn or Joy with 1 gallon of warm water.

Straws, string, trays, paper towels. 

Plastic 2 liter soda bottles.

Explorations:  

Bubble in a Bubble

After wetting your tray or table top with bubble solution, blow a large bubble on the surface of your tray. Next wet your straw with bubble solution and gently push it through the large bubble. Blow a smaller bubble inside the larger one and then go for three and even four if your feeling giddy. 

Guiding Questions: 

1.  Why do you think bubbles are normally round in shape? 

2. Why doesn't the bubble burst when it is pierced by the wet straw?  

3. Do you think it would still work if you used a dry straw? Try it and find out. 

Bubble Combinations

Start by wetting the tray or table top with bubble solution. Next, dip your straw in to the bubble solution and holding near the wet surface, gently blow through the straw. If you blow carefully, you will be able to form a bubble in the shape of a hemi-sphere (half of a sphere). Practice this technique by making bubbles of several different sizes on your tray. 

Now that you have learned the technique, blow several bubbles that are about the same size but do not touch each other. Then you can move them toward one another by blowing on the bubbles gently with a straw. As the bubbles begin touching each other, observe them closely and try to determine the shapes that the bubbles form.  Finally, using five bubbles in a pattern, try to make as many different patterns as possible. 

Guiding Questions:  

1. What happens to the bubbles when they touch?

2. What shapes do they form?

3. Why do you think that they form these shapes?    

4. Sketch each of the shapes that you were able to form using five bubbles. 

The Hawaiian Hula Dancing Bubble 

Using a scissors or knife, cut away the midsection of an empty bottle and discard it. Keep the bottom base as your soap container and trim the top section to that it can rest inside the bottom base. Fill the base with soap solution to about 1 cm from the top. Place the top section into the soap solution and move it around to wet the rim. Next, gently blow into the bottle from a short distance away and as you do so lift the bottle from the base to form a new body (midsection) for the bottle. Although this bubble will begin to pinch off in the middle, this process can be stopped by screwing the top back onto the bottle. 

By gently shaking the top of the bottle, the bubble will shake and resonate like a professional hula dancer. Take turns having your students create and gyrate their own hula dancers. If you can, play some Hawaiian music to add to the atmosphere. 

Guiding Questions:

1. Why do you think it is necessary to blow in the bottle in order to establish a lasting bubble?

2. After exploring bubbles in investigation, what is one summary statement that you could make that explains why bubbles prefer certain shapes?    

Explanation:

Concept Explanation:

      Bubbles are bits of air or gas trapped inside a liquid ball. The ultra-thin liquid ball that forms the surface of the bubble is made from a film which consists of a little soap and a lot of  water. Because the water molecules in a bubble attract to each other, they try to pull together and, as a result, they always form in a shape that takes the smallest surface area possible (usually this is a sphere). This helps make them more stable.  Bubbles are always delicate but they are particularly fragile when a dry object touches them. That's because soap film tends to stick to the object and this puts a strain on the bubble. So if you want your bubbles to last longer, keep everything that they touch wet. By blowing into the Hula Bubble as it forms, the air pressure on the inside and outside are equalized and this helps to stabilize the bubble. But remember, bubbles (like other liquids) always form a shape that makes them as small as possible. 

Objectives Covered:

QCC # 1. 1 - 5.1    Science Inquiry, Process Skills, and Problem Solving

The student will ask questions, make and keep simple records of observations, sort and classify objects, communicate with others, make predictions, use estimation and measurement, and make sketches and diagrams to explain ideas.