Some of my favorite memories from childhood include running around, blowing bubbles in my backyard. A neon bottle of bubbles in one hand, a matching plastic wand in the other and I was ecstatic with my long braids flowing behind me as my laughter filled the air. My favorite part was looking at the rainbows that could be seen as the bubbles twinkled in the sunlight. I never stopped to think about the scientific implications of this activity or what I could learn from my endless hours of fun. But, learning about the science behind bubbles serves to benefit us all.
Have you ever looked at a bubble and noticed the colors of the rainbow reflected back at you? Despite their transparency they sometimes show hints of color which are the aforementioned rainbows and my favorite part of bubbles. This is due to iridescence which occurs when light passes through a bubble. Bubbles are characterized by two layers of soap surrounding a layer of water. Think of it as a water sandwich with soapy bread. Disgusting to eat yet beautiful to look at, when light passes through one of three things will happen next. Either the light will reflect off of the outer layer of the bubble, the light will enter and bounce off of the inner layer before exiting, or it will enter and bounce between the two layers before exiting.
There are now two new bubble exhibits in WonderLab’s gallery available for visitors to fall in love with them, too. One of these is Bubble Domes. This exhibit features air flowing through three tubes positioned over a basin of bubble solution. Visitors can dip the tubes into the solution to blow a bubble dome or raise the tube up to create a bubble at the end. During one of my earliest interactions with this exhibit, I lost track of time as I blew bubbles onto one another again and again.
The shape of a bubble has scientific properties. Most bubble wands are circular, so the fact that bubbles tend to form spheres is not entirely surprising. But, have you ever tried blowing bubbles using a wand with a different shape? When I first used the triangle and square bubble wands at WonderLab, I could not figure out why my bubbles still came out as spheres.
I now know this is due to surface tension. Surface tension is the tendency of liquids to pull tightly into themselves to form the shape with the smallest surface area possible. A sphere is the shape with the smallest surface area relative to its volume, so bubbles form this shape to achieve pressure equilibrium between the liquid bubble solution and the air being blown into it. However, it is possible to blow bubbles in the shape of a cube. When bubbles are blown touching each other, a flat surface is formed because there is equal pressure coming from both sides. Blow six bubbles, two vertical and four horizontal, then blow a bubble in the middle of them and watch as it forms a cube. Fellow editorial intern Niha and I gave this trick a shot at Bubble Domes and our results were hilarious though not cube-shaped. I encourage all visitors to try for themselves. Also, if you let the tubes blow bubbles on their own, sometimes enough will form for bubbles to take the shape of cubes between each other. I caught a video of this last time I walked by, see if you can find the cubes yourself! (Image #3)
The other new exhibit is Foam Fountains. This exhibit features two long tubes constantly blowing bubbles which results in foam. The foam runs down and out of the tubes onto the table underneath it. Play with the foam next time you come by. When I spend time at the fountains, my hands come away coated in the thick solution created by the constant flow of bubbles.
Foam is made up of many bubbles touching each other. Some places it can be seen are in fizzy sodas, fire extinguishers, and WonderLab’s Foam Fountains. Foam is made when the surface tension of water is decreased through surfactants. As the bubbles are formed, they grow together more quickly than they pop which creates foam. Foam has many uses, both practical and fun and here at WonderLab we focus on the fun. Take some time to hang at Foam Fountains the next time you stop by and feel the bubbly mess it creates. This foam is thick enough for visitors to pull from the mouths of the exhibit. I like to gather the bubbles and create some foam art. Can you?
With winter fast approaching, try this cool bubble trick. Bubbles are capable of freezing thanks to the layer of water within the layers of soap. Because they tend to pop quickly, it is difficult to drop the surrounding temperature fast enough to freeze the bubble. However, if you manage to achieve a frozen bubble, you will have a beautiful, delicate relic of snow day fun. I have tried on many occasions to freeze bubbles in my backyard, but no such luck. A piece of advice for those who do manage to freeze their bubbles, don’t get too attached because once the air inside leaks out, the bubble will collapse in on itself. If you can not wait for colder temperatures to play with frozen bubbles, check out this video by a man who froze bubbles for his daughter.
Bubbles, bubbles, bubbles! WonderLab has always had an appreciation for these soapy wonders and the science behind them, which is one of my favorite parts of interning here.
My time at the bubble exhibits is the most fun I have ever had while working and I always come away with more knowledge gained through play. So next time you whip out a bottle of bubbles for a fun day of play, look out for the scientific applications that can be explored anywhere. (Image #6)
- Uncover Science
- Science facts about bubbles
- Science Foam and Physics
- Frozen Bubbles
- Non-Newtonian Physics Group
- The Definition of Foam
About the Author: Brittney is a junior at IU majoring in journalism and public relations. She loves blowing bubbles made of soap, gum, and everything in between. Her favorite part of working at WonderLab is getting to play with the bubble exhibits as much as she wants.