It attempts to describe and account for the properties of molecules and atoms and their constituents—electrons, protons, neutrons, and other … Quantum mechanics is the body of scientific principles that explains the behavior of matter and its interactions with energy on the scale of atoms and subatomic particles and how these phenomena could be related to everyday life. Quantum mechanics is the science of very small things. Likely, quantum computers are generalized versions of classical computers, but that won’t mean classical computers will become obsolete in a few years. If its mass were one mole, fourteen grams, it would contain 6 × 1023 atoms. ... : 24 So when physicists first discovered devices exhibiting the photoelectric effect, they initially expected that a higher intensity of light would produce a higher voltage from the photoelectric device. Physicists know that classical mechanics is wrong, and quantum mechanics is right, yet classical mechanics is perfectly fine to model stuff we interact with in our daily lives. Much for the same reason people argued against special relativity: non-mechanical interaction. It’s very ironic actually. Even though there are many things that are highly confusing about quantum mechanics, the nice thing is that it’s relatively easy to apply quantum mechanics to a physical system to ﬂgure out how it behaves. But qm does provide a so-far-unchallenged accurate description of … They will remain more than enough for our practical purposes. Quantum mechanics, science dealing with the behavior of matter and light on the atomic and subatomic scale. So, to take one example, how does quantum mechanics make the laser possible? Typically, quantum mechanical systems consist of a few particles.3 The number of particles in ordinary macroscopic things, however, is inconceiv- ably vast. these in an actual course on quantum mechanics. So now quantum mechanics comes along, begging you to ask, "What is a particle ?" There is fortunately no need to understand all of the subtleties about quantum mechanics in order to use it. (Magical thinking) Einstein called it “spooky action at a distance” when referring to QM. For example, imagine a small pellet of carbon that you could hold between your ﬁngers. And then providing what seems like a totally unsatisfactory unintuitive semi-answer. At least that's how it seems today.