BUBBLE SCIENCE

Introduction

Everybody loves bubbles. It brings a sense of joy and wonder to ones who see them. But, how are bubbles formed? What makes them float up in the air? Can these simple, yet amazing, things be used as a tool for teaching science? Yes, it can. Science is an inspiring discipline; one that nurtures natural curiosity and provides a platform for investigation. Unfortunately, traditional instruction misrepresents science to be a body of facts that is to be memorized and as a rigid 5-step subject. This suppresses the students’ spirit of inquiry. Bubbles are a simple, yet amazing, way of teaching science in a fun and interesting manner. We can explore concepts like elasticity, surface tension, interference of light, geometry, and many other topics through the use of bubbles. In this article, we will focus on learning about surface tension of a liquid and how that affects the formation of bubbles.

  The secret to blowing a good bubble is something called “surface tension”, an invisible bond that holds water molecules together. Water is a polar molecule. So, it has positive and negative ends, just like magnets, which attract each other. When the water molecules align with each other, they stick together and create a surface tension.

You might think that the higher the surface tension of the water, the better will be the formation of the bubble. However, the surface tension of water is too strong to make a bubble. You can try to blow a bubble with plain water; it just won’t work! A good bubble solution has a detergent added to it in order to reduce the surface tension of the water, allowing it to have more elastic and stretchy properties. After detergent has been added to the water, it can act more like the skin of a balloon—stretching out nice and thin, trapping air inside of the bubble just like a liquid balloon.

TRY IT YOURSELF!

Take some water in a tumbler and sprinkle some fine powder (talcum powder) on the surface. What do you see?

Now, add a drop of liquid detergent to the water and see what happens.

As we add the detergent, the surface tension of the water decreases, and the powder begins to settle at the bottom.

Bubble Challenge

What do you need to make a good bubble solution at home? The basic ingredients include water and detergent. In this “challenge” (Experiment), we added glycerin, corn syrup, and sugar to see if these elements would help us to make better bubbles. We wanted to test which combinations of solutions would produce bigger bubbles and which bubbles would retain their form for a longer period.

Requirements: Glass jars with lids (recycled jars work fine), Measuring cups and spoons, Distilled water, Liquid dish-washing soap (e.g. Pril, Vim), Glycerin, Small bottle (available at a pharmacy), Light corn syrup, Pipe cleaners, Permanent marker, Stopwatch.

To find which of the following make a good bubble solution

The above solutions were prepared using the combinations as given in the table above. Three hoops of the same diameter were made using straw or pipes. These hoops were then used to test the bubble solution. The hoop was dipped in the solution, and the bubbles were made. The stopwatch was used to record the longevity of bubbles. The bubble-making process was repeated, and the concurrent data was collected. The average was taken to determine the mean longevity of bubbles formed by the various solutions. The values were plotted in axes, and the data was represented graphically. These experiments were repeated in the winter as well as in the summer to understand if there were any other factors that influenced the quality of the bubble.

Results

In a closed room, the bigger bubbles that were formed lasted for about 4 minutes during winter and 1.35 minutes in the summer. Out in the open, the bubbles lasted for about 2.40 minutes in the winter and 35 seconds in the summer.

Reflections

At first, the students tried to form bubbles with soap solution. They were able to produce small bubbles, which would not last for a long time. After the instructions were given to them properly, the students were able to make bubbles that lasted longer. Hence, the part of teacher in facilitating and giving instruction is very important in facilitating learning.

Further, making bubbles, holding them back on hoops, and collecting data was not an easy task. The students had to repeat their experiments a number of times. Trial and error had been a constant part of the experiments. Hence, the students had to repeatedly try and practice their skills to obtain nearly concurrent results. This exercise also motivated the students to look at common phenomena in a scientific manner.

Way Forward

DID YOU KNOW?

Water striders (நீர் சவாரி) are small insects that are adapted for life on the surface of still water. They use surface tension to their advantage so that they can “walk on water”.

Going forward, my students and I would like to work more on environment-related aspects such as pollution. Certain areas of bubble science that we would further like to explore would be to check how long bubbles can last in polluted air or water. Could bubbles help in indicating pollution and, thereby, also help us in conserving the environment?

Author: D. Aravindaraja, GMS, Mudaliarpet