Matter & Change

Icy Brinicle of Death: A COOL Example of Freezing Point Depression

What real world examples are made known to students when discussing freezing point depression? What about brinicles, also known as "Icy Fingers of Death"? A brinicle (from brine + ice) is a finger-like formation of supercooled brine solution that grows downward underneath sea ice. Intrigued? Cool (pun intended). Keep reading to find out more!

Photochromic glue and spring decorations

The many colors of springtime can be illustrated with photochromic pigments in commercial products. These products include UV beads, and more recently, photochromic glue. The glue can be used as a photochromic paint for paper or even eggs. The resulting colorful, decorative objects can be used to illustrate chemical discussions of aspects of photochemistry.

The Carbon Dioxide Spiral Staircase

The demonstration where CO2 is generated and used to snuff out a candle in an aquarium or other container is well known. This article describes a dramatic variation on these demonstrations that allows for discussion of such topics as the ideal gas law, densities of different gases, gas density changes with temperature, miscibility, and viscosity. The device described is easily and inexpensively produced and stored. The demonstration is large scale and works well for classrooms and community outreach events.