Electrons - Particles? Or Waves?

The Uncertainty Principle of quantum theory states that both the position and the momentum of a particle cannot be simultaneously and precisely measured. The more precisely the position (or momentum) of a particle is measured, the less precisely one can measure what its momentum (or position) might be. This principle has profound implications for both the classical concept of cause-and-effect and the determinacy of past and future events.

This excerpt from a BBC documentary examines the scientific climate which existed around Werner Heisenberg's development of the Uncertainty Principle -- including Einstein's and Curie's fierce opposition to it. It further delves into the stranger-than-fiction behavior of electrons first discovered in the early 20th century, the wave-particle duality problem, and the invention of vacuum tubes, transistors and semiconductors.