Laser-Cutting CDs into Snowflakes

Laser cutters can be used to cut and engrave a variety of thin materials. Compact discs, composed of layers of polycarbonate plastic and aluminum metal, were explored for their ability to be shaped with a laser cutter. The laser can successfully cut and engrave the compact discs into the shape of snowflake. However, each disc must first be coated with a material like glue in order to protect the plastic from discoloration and the byproducts from cutting the plastic that can accumulate on the disc surface.  

The Pumpkinator

This Pumpkinator is a fantastic orange-to-blue-to-orange chemical reaction that will make a great addition to your Halloween-themed chemistry demonstrations.

Using My Marbles: Connecting Surface Area and Calorimetry with Temperature Curves and Thermochromic Cups

The importance of surface area can be illustrated by adding spherical solids at known sizes and temperature to other substances at different temperatures and then monitoring the rates of temperature changes of the system over time. Larger spheres (with less surface area per sample) exchanged heat with water more slowly than smaller spheres, and less thermally conductive glass spheres exchanged heat with water more slowly than iron spheres. Additional, more colorful demonstrations are described in which small glass spheres cool thermochromic plastic cups more quickly than larger glass spheres. 

A Polystyrene Model of Polystyrene Tacticity

Thin sheets of polystyrene can be patterned with permanent markers to represent repeating units of the polymer and then shrunk down in size using heat. The shrunken models of the repeating units can be connected with a string and then flipped into positions to demonstrate different types of polymer tacticity.