Freezing soap bubbles

Want to try an easy, yet interesting chemistry experiment this winter? Try this: Blow some bubbles into the outside winter air and catch one of the bubbles with a bubble wand. If it is cold enough outside, the bubble will freeze! 

The recent Polar Vortex has brought some pretty cold temperatures to Michigan where I live, and I’ve been conducting this simple “freezing bubble” experiment over the past few days. In the video below, you can see the results of some of my experiments.  These experiments were conducted at or below 0°F (-18°C).

Below I will share both tips I have learned and questions I have pondered while conducting this experiment. I’d love to hear from those of you who have tried this experiment or have any comments or ideas about it.

I have not been able to successfully freeze a bubble in windy weather. The bubbles are just too hard to capture on the bubble wand when it gets too breezy. Besides, any bubbles that are captured get popped by the wind before freezing. 

I have a lot of questions about the effect of temperature on this experiment. It takes a bit of time for the bubbles to freeze, and it seems to take longer at higher air temperatures. This experiment works very well at temperatures at or below 0°F). It also works at temperatures as high as 25°F (-4°C). However, the bubbles frozen at warmer temperatures tend to form in a more amorphous, less spherical, less crystalline fashion. Below you can see a bubble freezing at around 25°F. Compare it to the bubbles formed at below 0°F in the video above.    

I noticed that shining light on the bubble from below and viewing the bubble from above greatly facilitated the observation of crystal formation on the bubble surface. Furthermore, it was much easier to see the crystal formation at night, so long as the bubbles were illuminated with a flashlight. 

Finally, I wonder if this experiment could be conducted indoors. Could bubbles be frozen by immersing them in parcels of air cooled by dry ice or liquid nitrogen  Wouldn’t that be cool?  Then this experiment could be conducted in the middle of the summer!  



General Safety

For Laboratory Work: Please refer to the ACS Guidelines for Chemical Laboratory Safety in Secondary Schools (2016).  

For Demonstrations: Please refer to the ACS Division of Chemical Education Safety Guidelines for Chemical Demonstrations.

Other Safety resources

RAMP: Recognize hazards; Assess the risks of hazards; Minimize the risks of hazards; Prepare for emergencies