What is a standing wave in an atom?

A standing wave is a wave that maintains a fixed pattern instead of travelling. In an atom, the electron's matter wave wraps around the nucleus and only forms a stable pattern when a whole number of wavelengths fits along the path. Fractional wavelengths cancel themselves out and are not allowed.

What is the quantization condition for electron orbits?

The quantization condition is nλ = 2πr, where n is a positive integer, λ is the de Broglie wavelength, and r is the orbit radius. Substituting λ = h/mv gives Bohr's familiar condition mvr = nh/2π. Both forms say the same thing in different language.

Why are s-orbitals spherical?

An s-orbital is the lowest-energy 3D standing wave around a nucleus, with no angular nodes. Since the only solution with this symmetry is one that depends solely on distance from the nucleus, the electron probability is the same in every direction — making the orbital perfectly spherical.

How does this lab relate to Bohr's model?

Bohr drew electrons in flat circular orbits, which was a useful first approximation but physically incomplete. This lab shows the upgrade: the electron is really a 3D standing wave wrapped around the nucleus. The quantization that Bohr postulated emerges naturally from the wave fitting condition.

What happens if the wavelength doesn't fit a whole number of times?

If a fractional number of wavelengths tries to fit around the nucleus, the wave overlaps itself out of phase on each loop and cancels by destructive interference. Only wavelengths that close cleanly survive. This is why electron energies in atoms come in discrete levels.

PhysicalMediumNEET: 1-2 Q3D

Physics lab

Matter Waves 3D — Standing Waves Around the Nucleus

Dual Nature of Radiation and Matter

Explore the interactive model.

Loading lab

interactive — tap or drag to explore

How to use this lab

1Particle select karo aur uski de Broglie wavelength λ dekho.
2Heavy particle → λ itni chhoti ki wave practically gayab.
3Canvas ko drag karke 3D wave ghumao.

About this lab

Watch a 3D electron wave wrap around a nucleus. Rotate it with your finger. At integer wavelengths the wave closes cleanly — at fractions it fails. The same standing-wave principle that explains why orbits are quantized, in 3D.

Next lab

Heisenberg Uncertainty — No Fixed Path

Atoms & Modern Physics

→

🧭 How to use this lab

About this lab

How to use this lab