physics

BLACKBODY RADIATION

Interactive simulation of Planck's law. Explore how temperature affects spectral radiance, color, and Wien's displacement law.

Spectral Radiance Plot: Wavelength vs. intensity. Color gradient represents visible spectrum. Dashed line shows Wien's peak.

Temperature Control

Temperature
5778
K (Kelvin)
300 K — 40000 K

Star Types

Display Options

Blackbody Color

Star Type: Sun (G-type)
Color Temp: 5778 K
Wien's Peak
501
nm
Peak Frequency
597
THz
Radiant Power
6.37e7
W/m² (Stefan-Boltzmann)
Peak Photon Energy
2.48
eV

About This Simulation

Planck's Law describes the spectral radiance of electromagnetic radiation emitted by a blackbody in thermal equilibrium at temperature T.

B(λ, T) = (2hc² / λ⁵) · 1 / (e^(hc/λkT) − 1)

Wien's Displacement Law tells us the wavelength of peak emission:

λ_max = b / T, where b = 2.898 × 10⁻³ m·K

Stefan-Boltzmann Law gives total radiant power per unit area:

P = σT⁴, where σ = 5.67 × 10⁻⁸ W/(m²·K⁴)

The Ultraviolet Catastrophe: Classical physics (Rayleigh-Jeans) predicts infinite energy in short wavelengths. Quantum mechanics (Planck) fixes this by quantizing energy. Toggle the Rayleigh-Jeans curve to see the dramatic difference!