Physics

Quantum mechanics

 * Classical randomness: statistical randomness in the energy - energy wouldn't be exactly conserved in a world in which
 * Quantum randomness: energy is exactly preserved but movement is somewhat random
 * Double slit experiment: two holes through which photons are shot with a little random kick. The points at which they hit the wall create a probability distribution of the likelihood of the photon hitting that point. According to classical logic, the probability of any point being hit is the combined probability distributions of the two holes (chance of photon going through hole A and arriving at point X and probability going through hole B and arriving at point X). See Graaph 1Double-slit_experiment.jpg. If you conduct the actual experiment, the probability looks more like Graph 2 Double-slit_experiment_-2.jpg. What happens here is that the probabilities, instead of adding up, cancel each other out at the 0-probability points → destructive interference


 * Beams of light not only have energy but they also have momentum: if you shine a beam of light on something, it will warm it. That tells you it has energy. But you can also take it and if it is strong enough it kicks a door open