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.
Beautiful, metallic mirrors of copper or silver can easily be formed in test tubes. Simply add the appropriate metal salt to a test tube, and heat! These reactions should be performed in a fume hood.
Learn how to thermochemically analyze the Devil's Milkshake chemical demonstration - just in time for Halloween!
The application of Hess's Law frequently presents students with conceptual problems. This series of experiments confirms Hess's Law and offers a robust understanding of this principle. This can be done as a demo completed by the teacher or as a lab with groups of students.