Unit 1 · The Classical World Cracks
Chapter03
Blackbody Radiation & Planck's Desperate Act
The ultraviolet catastrophe, and the 1900 guess that started a revolution
Quantum Academy · presented by Dr. Quincy Quantenstein
CH 03X–Y
0:00 / 40:28OpeningTitle
Watch the lesson · Unit 1: The Classical World Cracks
Blackbody Radiation & Planck's Desperate Act
The ultraviolet catastrophe, and the 1900 guess that started a revolution
- ≈ 40 min
- 54 scenes
- Narrated by Dr. Q
- Captions
Generated from the same script as the written lesson, so every word matches the text. Uses your device's voice when it has one; without one, the lesson plays silently with captions. Keys: Space play · ← → scenes · C captions · F full screen.
By the end you'll be able to
- Define a blackbody and explain why its glow depends only on its temperature, using stove elements, stars and the cosmic microwave background as examples
- Use Wien's displacement law and the Stefan-Boltzmann law to find peak wavelengths, temperatures and radiated power
- Read a star's temperature from its colour, and explain why white-hot is hotter than red-hot
- Explain how counting standing-wave modes and giving each one kT produces the Rayleigh-Jeans law and its ultraviolet catastrophe
- State Planck's hypothesis E = n·hf and explain how the Boltzmann factor freezes out high-frequency modes
- Describe what Planck did, and did not, claim in 1900, and why he called it an act of desperation