Phase Transitions / Diagrams

Two Simple and Cheap Illustrations of Phase Equilibrium and Vapor Pressure

A favorite demonstration is to boil water by lowering the pressure in a bell jar using a vacuum pump. Unfortunately, purchasing a bell jar, vacuum plate, and vacuum pump can run upwards of $1,000 which poses a hardship for many teachers. Here are two simple and inexpensive demonstrations of phase equilibrium and vapor pressure.

Time required: 

 

Setup: 5 minutes

Execution: 5 minutes to 30 minutes depending on level of inquiry

 

Scrub Daddy Science

The science behind the incredibly popular Scrub Daddy sponge is investigated. Part of the appeal of the Scrub Daddy sponge is that it changes from soft to hard depending upon temperature. This allows a single sponge to be transformed into a hard scrubber or soft sponge, depending upon the temperature of water into which it is placed.

The Density Bottle Strikes Again

Density Bottles can be used to teach a variety of chemical concepts such as density, solubility, and polarity. In this post it is shown that Density Bottles can also be used to differentiate between heterogeneous and homogeneous mixtures, and to explore light scattering.    

JCE 94.05 May 2017 Issue Highlights

Lasting Value and High Impact

The May 2017 issue of the Journal of Chemical Education is now available to subscribers. Topics featured in this issue include: project- and inquiry-based laboratories; measuring value and impact; research on core ideas and clickers; new twists on classic activities; understanding diffraction; acid-base chemistry; teaching informed by technology: flipped learning, biochemistry labs, and scientific computing for chemists; from the archives: chemistry helps feed the world.

Simple, Small-Scale Dry Ice Explosions

A fun experiment to conduct when discussing phase diagrams is the melting of solid carbon dioxide (dry ice).  To perform this experiment, place small pieces of dry ice (carbon dioxide) in a plastic pipette, seal with a pair of pliers, and position the bulb of the sealed pi