1. What does it mean if something is quantized? Day 3 12-7

1. What does it mean if something is quantized?

Day 3 12-7

Continuous: VS. Quantized:Height by step or Height by step or rungrung

Height on slide or rampHeight on slide or ramp

Continuous: VS. Quantized:

Radiant Energyis energy that travels travels through spacethrough space.Is also known as lightlight and

electromagnetic electromagnetic radiationradiation.

Major source is…THE SUNTHE SUN

Radiant Energy…Sun’s radiant energy

is the result of nuclear fusion.Nuclear fusion – light nuclei combine to form heavier nucleiFission vs. Fission vs. fusion?fusion?

The dual nature of lightParticle??? Wave???

The dual nature – light can be viewed as a wave (continuous) OR a stream of extremely tiny, fast-moving particles (quantized)

The dual nature of lightParticle??? Wave???

- Wave (continuous) as it travels through space- Particle (quantized) as it interacts with matter

Electromagnetic Spectrum

The ordered sequenceordered sequence of all types of lightlight or electromagnetic electromagnetic radiationradiation.

The part of the electromagnetic spectrum that humans can see is called the …

radio, micro, radar, IR, vis.

Electromagnetic Spectrum

vis., UV, X-ray, gamma, cosmic

Low, low

& Long!

High,

high &

short!

Violet-Violet-High High energy, energy, bends more, bends more, inside of inside of rainbow, rainbow, 400 nm400 nm

R O Y G B I V

Red-Red-Low Low energy, energy, bends less, bends less, outside of outside of rainbow, rainbow, 700 nm700 nm

Sir Isaac Newton……in the 1670’s, in the 1670’s, diffracted light diffracted light with a with a prismprism and…and…Concluded that Concluded that each color of light each color of light has a unique has a unique wavelength… wavelength… energyenergy

Electromagnetic Spectrum

ha

amplitude (a) - affects amplitude (a) - affects brightness, brightness, half the half the height height Frequency (Frequency (νν) = number of ) = number of crests passing a crests passing a point in a point in a period of time period of time h = height, from crest to h = height, from crest to troughtrough speed (c) = distance per speed (c) = distance per unit timeunit timewavelength (wavelength (λλ) = crest to ) = crest to crestcrest

λ = c/νwavelength

speed of light

frequency

Radiant AcrosticRADIANT

DEFINE:

energy level AND atomic orbital

AND Read section 5.1 AND answer

questions 1, 2, 4, and 5 on page 132

2 definitions and 4 questions

Day 2 12-6

1. Amplitude affects __________.2. Longer wavelengths = ______

frequencieslower

brightness Day 4 12-8

How do we know that atomic energies are quantized?

Day 4 12-8

Note page 2:

If a light wave has a wavelength (λ) of 3.0 * 10-7 m, what is its frequency?

λ = c/νwavelength

speed of light

frequency

C = 3 * 108 m/s 1.0 * 1015

Hz

Radiant Energy…The dual nature of

light?

Quantum TheoryBeginning of 20th century – wave model is almost universally accepted.Problem = electromagnetic radiation emitted from hot objects

Can all light be described asThe energy of waves is continuouscontinuous, or unbroken…When we look at an object as it is heated, what do we see?

Quantum Theory

… - quanta

Stop and summarize

Each color has its own Each color has its own energy energy AndAnd the the energy changes with energy changes with heatingheating

Quantum Theory

… - quanta

Max Planck- related the frequency of light to its energy energy with the following: E = h E=EnergyEnergy, h=Planck’s h=Planck’s

const.const.His idea was that energy is absorbed and released in specific amountsspecific amounts.

Quantum Theory

6.626e-34 J*s

His idea was that energy is absorbed and released in specific amountsspecific amounts. He called one piece, package, or bundle of energy one quantumquantum. Bundles of energy were called quantaquanta. He applied his quanta ideas to energy changes in atomsatoms:

Quantum Theory

He applied his quanta ideas to energy changes in atomsatoms: The energy of atoms is quantizedquantized. Formerly, scientists had thought that all energy was continuous continuous (wave-like)(wave-like).

Quantum Theory

Democritus’ Democritus’ atomatom

Quantized QuantizedMatter: Energy:PlankPlank

Continuous: VS. Quantized:Height by step or Height by step or rungrung

Height on slide or rampHeight on slide or ramp

Continuous: VS. Quantized: Ice cream scoopsIce cream scoopsSoft-serve ice creamSoft-serve ice cream

Quantized: VS. Continuous:escalatorescalatorstairsstairs

Continuous: VS. Quantized:Cheese singlesCheese singlesCheese blockCheese block

Quantum TheoryCome up with your own:Continuous VS. Quantized:AND put it in your notes!

Albert Einstein - Imagined that light energy traveled in bundles - photons.18 years later, Arthur

Compton experimentally demonstrated that light is comprised of tiny particles, or photons,

Quantum Theory

TODAY- Planck’s term quantum and Einstein’s term photon are used interchangeably.

demonstrated that light is comprised of tiny particles, or photons, that can collide with electrons and cause them to move.

Quantum Theory

TODAY- Planck’s term quantum and Einstein’s term photon are used interchangeably. Scientists also believe that light has properties of both waves and particles.

Quantum Theory

… - Dual nature of light

h

a

radio, _______, radar, IR, vis.vis., ___, X-ray, gamma, cosmic

_________

&

Long

________

& Short!

λ = c/ν

Violet-Violet-______ ______ energy, energy, bends more, bends more, inside of inside of rainbow, rainbow, 400 nm400 nm

R O Y G B I V

Red-Red-_____ _____ energy, energy, bends less, bends less, outside of outside of rainbow, rainbow, 700 nm700 nm