Describes an exercise that allows the measurement of the sizes of biological samples by means of the diffraction of light. (JRH)

A simple experiment concerning the elasticity of wood is described that can easily be performed at home. The forces needed to produce a stress in wood are measured and compared. Provides a mathematical discussion of the elasticity and stress of wood. (MVL)

Discusses three broad classes of magnetic behavior: diamagnetic, paramagnetic, and ferromagnetic. Presents a simple lecture demonstration using an overhead projector to synthesize triiron tetraoxide and to show its interaction with a magnetic field and comparing it to a paramagnetic material. (MVL)

Finds that a logical application of the simple rules of the molecular orbital bonding theory for diatomic molecules predicted the existence of three spin isomers of the oxygen molecule: one triplet form with two unpaired electrons and two singlet forms with all electrons paired. (MVL)

Explained is a representation of the three categories of spectra. Discusses what a lesson on spectra should include, background information, and equipment needed. Provided is a diagram of an absorption box. (RT)