Demonstrating the Glass Transition of Polylactic Acid with a Rattle

Polylactic acid (PLA) exhibits a glass transition from hard and brittle to soft and rubbery when immersed in boiling water. PLA-based structures containing a small metal object can be used as rattles when they are shaken. The sound of the rattles change when they are heated above or cooled below their glass transition, enabling them to be used as demonstrations.

Colour Changes with Caffeine - Part 2

This study outlines the effect on the colour of anthocyanin-containing solutions when mixed with caffeine. Given the diversity of anthocyanin structures available from other vegetables, fruits or flowers, there is great potential for series of open-ended experiments for students in classes or science clubs to investigate.

Chemistry Topics

acids/bases applications of chemistry aqueous solution chemistry Atomic Properties / Structure conductivity consumer chemistry Demonstrations density electrochemistry electrolysis equilibrium Food Science gases General Chemistry kinetics Laboratory Instruction liquids metals noncovalent interactions Outreach Oxidation / Reduction oxidation/reduction Phases / Phase Transitions / Diagrams Physical Chemistry physical properties Polymer Chemistry precipitation/solubility Public Understanding reactions solids stoichiometry thermodynamics