phase changes

In an effort to better understand my high school students' knowledge of what is happening during phase changes, heating curve calculations, and the ever popular can crush demo, I run them through a series of activities.

A favorite experiment of mine is the bucket launch. My students and I recently tried two variations on this experiment. Watch the video below and see if you can explain the differences we observed.

I recently posted a video on Twitter of an experiment my students were conducting in class. I thought I’d blog about the experiment, since it seemed to generate a lot of interest.

Have you ever wondered where the cloud comes from when dry ice is placed in water? Consider the answer returned in my browser when I Googled the phrase “How does the dry ice cloud form”:

In Chemical Mystery #6, I used chemistry to crush a metal can. To do so, concentrated sodium hydroxide solution (about 35% NaOH by weight) was added to a can that was almost completely filled with carbon dioxide gas. The can was then sealed. The carbon dioxide gas in the can reacted with the added sodium hydroxide:

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!