Dr. Francis Crick describes the discovery of the double helix structure of the DNA molecule. Animations or diagrams illustrate. A model of a double helix is shown. Some people are conducting an experiment. A machine, possibly x-ray crystallography, is shown producing a graph or chart. Crick continues to describe DNA. A person uses a telegraph to send Morse code. Another person is shown using Morse code at a switchboard. A female scientist in a white lab coat is shown using a microscope and the sample is shown.