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Wave-particle duality​

Wave-particle duality is the concept in quantum mechanics that every particle or quantic entity may be partly described in terms not only of particles, but also of waves. It expresses the inability of the classical concepts "particle" or "wave" to fully describe the behavior of quantum-scale objects.

As Albert Einstein wrote

It seems as though we must use sometimes the one theory and sometimes the other, while at times we may use either. We are faced with a new kind of difficulty. We have two contradictory pictures of reality; separately neither of them fully explains the phenomena of light, but together they do.

https://en.wikipedia.org/wiki/Wave%E2%80%93particle_duality

Hysteresis​

the phenomenon in which the value of a physical property lags behind changes in the effect causing it, as for instance when magnetic induction lags behind the magnetizing force.

Quantum Mechanics​

https://publish.obsidian.md/myquantumwell/Welcome+to+The+Quantum+Well

A future with quantum biology - with Alexandra Olaya-Castro

Space​

Why West-to-East Flights are Faster​

The Jet Stream Effect

Flying from West to East is faster than flying East to West due to Jet Streams.

Key Points:

  • Atmospheric Rotation: The atmosphere rotates with the Earth, so the ground doesn't simply "slide" beneath the plane.
  • Jet Streams: These are high-altitude air currents that flow from West to East.
  • Tailwind vs. Headwind: Eastbound flights get a "push" (tailwind) from these winds, while Westbound flights must fight against them (headwind).
  • Speed: While the plane's airspeed remains constant, its ground speed increases when flying East and decreases when flying West.

Fluid Dynamics: Garden Hose vs. Faucet​

The Garden Hose Effect​

When you put your thumb over a garden hose, you create a nozzle at the final exit point.

  • Continuity Equation: $Q = A \times V$ (Flow Rate = Area $\times$ Velocity).
  • Reducing the area ($A$) at the exit forces the velocity ($V$) to increase to maintain the flow rate ($Q$).

The Faucet Difference​

When you restrict a faucet (using the handle):

  1. Internal Restriction: The water speeds up inside the valve, not at the exit.
  2. Turbulence & Energy Loss: The high-speed water hits the wider internal spout walls, losing its kinetic energy to turbulence and friction.
  3. Aerators: Indoor faucets have aerators that mix the water with air to create a soft, splash-free stream, intentionally reducing velocity.

Summary​

  • Hose: Restriction is at the exit → High-speed jet.
  • Faucet: Restriction is internal → Velocity is lost before the water leaves the spout.