A common misunderstanding held by many chemistry students is that resonance structures exist as unique entities that oscillate back and forth. It is challenging to help beginning students understand that the "actual" structure is not any one of the resonance structures, but a hybrid of all. Simply put, we do not have an easy way of showing what a resonance structure looks like, so we use several fictitious structures to describe the one actual structure. This concept is then further confused by the fact that sometimes the resonance species contribute differently to the hybrid. We have found two ways to help explain the resonance phenomenon in both general and organic classes-a color analogy and modified resonance arrows.Many students believe mistakenly, that if you could somehow "take a picture" of a resonance molecule for just a moment, it would show one of the resonance structures. The color analogy works well in explaining resonance. Green is a combination of blue and yellow. Assume that we don't have a way of describing green except in terms of primary colors. We don't say that a green wall is blue one second and yellow the next. No matter how fast you take a picture of

Presented here is a simple analogy that has helped students in our classes grasp the concept of enzyme activity

Presented is a very simple demonstration that can be used in class or lab to show how many significant figures to report when using addition or subtraction.

These authors have written a computer program that creates a grading grid.

A simple demonstration that illustrates the relationship between molecular size and viscosity.