Some key concepts in quantum mechanics lead to rather startling results. In the quantum world, objects can be in two states at once and the outcomes of experiments can change depending on when, how and how often scientists make their measurements.
An electron can be either a wave or a particle depending on the design of the experiment. If electrons pass through a single slit in a barrier and then strike a phosphorescent screen, they make patterns indicating the arrival of particles. But if two slits are available, an electron “wave” interferes with itself, producing the alternating bands of an interference pattern on the screen (bottom). This wave-particle duality is a fundamental feature of quantum physics and applies to all “particles” (including photons, particles of light) and even to atoms and molecules. Experiments have, for instance, shown the wavelike nature of fullerene