Category Archives: Physics

Q: How does quantum computing work?

The original question was: Could you give a description of the principles behind quantum computing? And how is it that some problems have a better time-complexity when they’re run on a quantum-computer? Physicist: Particles and sets of particles are frequently … Continue reading

Posted in -- By the Physicist, Computer Science, Engineering, Entropy/Information, Math, Physics, Quantum Theory | 22 Comments

Q: What causes buoyancy?

The original question was: I know that the buoyant force on an object equals the weight of the liquid that it displaces.  However, I have some questions as to what it means to ‘displace’ a liquid,  for example, does an … Continue reading

Posted in -- By the Physicist, Physics | 3 Comments

My bad: If atoms are mostly made up of empty space, why do things feel solid?

Physicist: Thanks to a comment in the original post, I did a little research and found that I was wrong, wrong, holy crap wrong.  Here’s some of that comment: “The source of the ultimate “excluded volume” forces is entirely quantum … Continue reading

Posted in -- By the Physicist, Mistake, Quantum Theory | 30 Comments

Q: Why does relativistic length contraction (Lorentz contraction) happen?

Physicist: This probably should have come before the last post. Length contraction is a symptom of “tilted now planes”.  For someone moving past you events physically in front of them happen earlier than they should (according to you), and events … Continue reading

Posted in -- By the Physicist, Physics, Relativity | 24 Comments

Q: Why does Lorentz contraction only act in the direction of motion?

Physicist: A lot of things get messed up by relativity, like when and where stuff happens, how massive things are, or how time passes.  Length contraction is an effect that literally makes things shorter in the direction of motion.  So … Continue reading

Posted in -- By the Physicist, Physics, Relativity | 22 Comments

Q: If atoms are mostly made up of empty space, why do things feel solid?

Physicist: (The following paragraph is wrong.  Like, really wrong.  There’s a redaction here: My bad: If atoms are mostly made up of empty space, why do things feel solid?) As atoms get too close to one another their charges begin … Continue reading

Posted in -- By the Physicist, Particle Physics, Physics | 72 Comments