Bubbles and Surface Tension

Posted on March 3rd, 2011

This is one of our newest and most popular activities.  During the “Bubbles and Surface Tension” lesson, Lab Ratz explore the tendency of water molecules to stick to one another, known as surface tension.  Because of this, objects that are much denser than water, such a paperclip, can be floated atop the water – The molecules of water simply will not separate to allow the paperclip to sink through them. 

When other molecules are dissolved in water and interfere with the ability of the water molecules to stick together the surface tension can be greatly reduced.  Molecules that do this are called surfactants.  Soap is used as a surfactant during this activity to make the surface of the water more “Flexible” and less “Brittle”, allowing us to make bubbles.  Try experimenting with the amount of liquid soap required to make the best bubbles and with the type of soap used.  Also, explore different methods and tools for blowing the bubbles.  Anything from a simple wire loop, drinking straw, paper funnel or even a wet towel can be used to blow bubbles through.  When you are finished, log on to Facebook and share your methods with us – We would love to hear what you have discovered!