Absolutely Small, Chapter 8: Quantum Racquetball and the Color of Fruit

A very simple problem is worked out that shows for absolutely small objects, energy is not continuous, but rather, can only come in discrete steps. The energy is said to be quantized. The illustration involves a discussion of what racquetball would be like when played on a court the size of a molecule. Results would be wildly different from racquetball on a normal-sized court. The results of the detailed description of the quantum racquetball problem (called the quantum mechanical particle in a box) are used to explain the absorption of light and color. It is shown why bigger molecules look red while smaller molecules look blue, thus explaining why blueberries are blue but cherries are red.