How to See Quantum Mechanics

Just look around you.

Everybody says that we can't see quantum effects. This turns out not to be the case. We see nothing else.

It is true that the uncertainty in position and momentum of visible objects is not directly visible. This is an instance of the Correspondence Principle, which holds that quantum effects dominate at the level of atoms and photons and smaller particles, but that the behavior of larger objects tends toward the Classical approximation. This is true, if you consider only bulk mechanical properties such as momentum and kinetic energy and temperature and pressure. It simply doesn't apply in the realms of light and chemistry and radioactivity, which have no adequate Classical explanations.

Many quantum phenomena are observable, if you understand what you are looking at.

Here are a few examples. I'm skipping superfluids, superconductors, microwave ovens, LEDs, lasers, and molecular biology, along with a lot of other phenomena, both rare and common.

• The first hint of quantum mechanics was that classical physics predicted infinite radiation from glowing hot objects, which of course was never observed. You have observed that fact yourself with great frequency. Max Planck worked out the solution, emission of quanta of light (photons) of specific energies, and won a Nobel Prize for it.
• Planck's explanation showed that color is a quantum effect, due to the varying energy of photons in the visible range.
• The second hint of quantum mechanics was Albert Einstein’s explanation of the photoelectric effect as absorption of photons, for which he won a Nobel Prize. We use the photoelectric effect in light meters and digital cameras, many of us all day, every day.
• The third hint of quantum mechanics was the spectra of various elements, which Niels Bohr partially explained with photons and with energy levels of electron orbits in atoms, and others greatly refined with quantized electron orbitals and fine and ultrafine properties of atomic spectra. Several of them won Nobel Prizes. There are various ways to view spectra explicitly, including prisms and diffraction gratings, but we can often get a good approximation just from ordinary colors, for example in grass and leaves.
• The famous double-slit experiment produces an interference pattern rather than images of the separate slits, even when only one photon at a time is sent toward the slits. There is much argument over the ideas that photons go through both slits at the same time, or it is only the probability wave that is in both slits. Since neither is observable without destroying the interference pattern, we will ignore the question here.
• We can see only because we have chemicals in our eyes that absorb photons. Three of them support color vision by absorbing photons preferentially in different energy bands.
• Rainbows, the “fire" in diamonds, and dispersion of light by prisms are quantum effects, due to the different speeds of different colors of light inside water droplets, carbon crystals, and glass, explained in Quantum Electrodynamics (QED).
• Cherenkov radiation, the blue light often seen inside nuclear reactors, is a quantum effect coming from electrons moving at faster than the local speed of light in water (¾c) or another transparent medium.
• Atoms are very complex quantum systems. At the first level, they are made of electrons, protons, and neutrons. But then the protons and neutrons consist of up and down quarks plus gluons. We do not know what those are made of, although we have some ideas, such as string theory. We cannot see the constituents, or individual atoms, but we can see aggregates of atoms, including the 219 shapes of crystals that elements and compounds form, and we can see such atomic effects as fire, boiling of liquids, and dissolving one substance in another.
• All of chemistry comes down to properties of chemical bonds, which come down to energy levels of electrons in different orbitals, including orbitals shared between atoms, and thus to quantum mechanics. The results of many chemical reactions are readily visible.

• In Classical physics, electrons orbiting nuclei (the Bohr planetary model) would instantly radiate away all of their energy of motion and collapse into the nuclei. Any object whatsoever that is made of atoms can only exist as such because electron orbitals are quantized.
• The various elements, and isotopes of elements, emit photons of specific sets of energies, their spectra, when their electrons change orbitals or fill empty orbitals from outside. They also absorb photons of those energies. But if they had to match energy exactly, this would be impossible, due to Doppler effects in atoms bouncing around in a thermal distribution. Absorption is only possible because of the principle of quantum indeterminacy, aka uncertainty. So, again, anything you can see at all demonstrates this quantum principle by absorbing some colors of light and reflecting others.
• Various gems derive their color from specific quantum absorption lines of specific elements in particular colorless minerals: chromium in emeralds and rubies; iron, titanium, chromium, copper, or magnesium in various colors of sapphire; and so on.
• Various radioactive isotopes emit visible radiation. Radium is the best known. This is entirely a quantum effect due to emission of alpha particles (helium nuclei), beta particles (electrons and positrons), or gamma rays, any of which can react with other matter to produce visible light.
• Iridescent bird plumage, as at the top of this Diary, and soap bubbles are quantum interference effects produced in thin films or regular microstructures. Similarly for the grooves in CDs and DVDs, and diffraction gratings.

• Quantum Entanglement Visible to the Naked Eye

• Stars, including our Sun, shine by energy generated from nuclear fusion, which requires quantum tunneling.
• We come from the Big Bang, and we are, as Carl Sagan said, star stuff. We are all part of the one cosmic wave equation, even though we can't yet write that equation correctly.

In other words, the light that we see by, everything that we see, and vision itself.

Note: This began as an answer on Quora: Is science anywhere near determining why our reality doesn't seem to behave the same as that on a quantum level?

I chose to point out that the premise of the question is incorrect.