US Library of Congress, LC-DIG-ggbain-35303

Anyone who is not shocked by quantum theory has not understood it.

-- Niels Bohr

https://commons.wikimedia.org/wiki/File:Wiens_law.svg

http://commons.wikimedia.org/wiki/File:Max_Planck_1901.GIF

“Black-Body Radiation”

Absorbs all colors

Model: Box with hole

Tiny leak of light from inside

Pipe Organ, Bath Abbey (UK)

𝜆1=2𝐿

𝜆2=𝐿

𝜆3=2𝐿3

𝜆4=𝐿2

𝜆𝑛=2𝐿𝑛

Standing Waves

Wavelength (arb. units)0.0 0.2 0.4 0.6 0.8 1.0

Num

ber of modes

0

2

4

6

8

10

Wavelength (arb. units)0.0 0.2 0.4 0.6 0.8 1.0

Num

ber of modes

0

10

20

30

40

50

𝜆𝑛=2𝐿𝑛

https://commons.wikimedia.org/wiki/File:Black_body.svg

“Ultraviolet Catastrophe”(Rayleigh and Jeans)

“Black-Body Radiation”

Absorbs all colors

Model: Box with hole

Tiny leak of light from inside

𝜆𝑛=2𝐿𝑛

“Black-Body Radiation”

Absorbs all colors

Model: Box with hole

“Oscillators” in walls produce light

Oscillators have characteristic energy

J-s “Planck’s Constant”

“Black-Body Radiation”

Absorbs all colors

Model: Box with hole

Oscillators have characteristic energy

ONLY INTEGER MULTIPLES OF ALLOWED

Quantum Hypothesis:

6 quanta

3 quanta

2 quanta

1 quantum

0 quanta

http://commons.wikimedia.org/wiki/File:Max_Planck_1901.GIF

Energy:

https://xkcd.com/54/http://hyperphysics.phy-astr.gsu.edu/hbase/bkg3k.html#c6

https://commons.wikimedia.org/wiki/File:Max_Planck_1933.jpg

Planck in 1933

http://commons.wikimedia.org/wiki/File:Einstein_patentoffice_full.jpg

𝐵 (𝜈 ,𝑇 )=2h𝜈3

𝑐21

𝑒−h𝜈/𝑘𝐵𝑇−1