Early evidence of Quantization
Day 4
Jumping activity
• Pair up- one of you will be the light source the
other will be an electron
• The electron will stand on the ground near the
stairs- this is the ground state
• When the light source delivers 1 quantum of
energy the electron can move up 1 step
• When the electron goes down one stair it has
to give up the difference in energy level
• Play around delivering quanta and switch roles
Human electron energy levels
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Level 1- 1 quantum
Level 2- 4 quanta
Level 3- 6 quanta
Level 4- 7 quanta
Level 5- 8 quanta
What happens if you deliver 2 quanta?
• Raise to level 1 but not enough to get to level
2!
• There is no intermediate level
The spectrum of the human electron
Level 5
Level 4
Level 3
Level 2
Level 1
ground
Flame colors
• http://www.youtube.com/watch?v=jJvS4uc4T
bU&feature=related
Emission spectra
How does the flame test and emission
spectra represent quantization?
• Flame test- the relaxation of electrons from an
excited state gives off a variety of energies ,
the mix is characteristic of the element
• Emission- this one is just like the human
electron example
How much is a quantum, exactly?
Planck’s hypothesis
• Essential to quantum mechanics
• All the radiation that is absorbed or emitted is
measured out in “quanta” – there is no such
thing as parts of a quantum
Homework
• You’ll use Planck’s hypothesis to figure out the
energy of the light given off in the emission
spectrum, given its color (wavelength)