Day 2 12-18
Get out your lab and sit in your assigned seat.
1. Locate your Chapter # 3 Test.
2. Calculate and record your % grade.
3. Did you meet your goal? Why or why not.
4. Study (preparation) Plan for next test?
5. Record your new goal:
- If you did not meet your goal it stays the same
- If you did meet your goal – improve by one percentage points
1. Average your first three test grades.
2. Your new goal must be:
A passing grade
at least a two point improvement of your average unless your average is an A in which case you must improve by one point instead of two.
Day 3 12-19
Hand in your lab now.
Get out your notes:
The dual nature of light says that light can act as a …
Day 6 1-5
How do we know that light is made up of particles?
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
The energy of green light compared to that of red light is ___________.
Sir Isaac Newton……in the 1670in the 1670’’s, 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
Read section 5.3 and answer #s 19-23 on page 148 – due Tuesday 12-23
Assignment
Light acts as a:
wave as it …
particle as it …
USE YOUR NOTES!!!
Day 5 12-23
Read section 5.3 and answer #s 19-23 on page 148 – due before you leave today
Assignment
Electromagnetic Spectrum
h
a
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 time
wavelength (wavelength (λλ) = crest to ) = crest to crestcrest
λ = c/νwavelength
speed of light
frequency
λ = c ÷ νλ = wavelengthc = speed of light = 3.00 * 108 m/sν = fequency (s-1, Hz, 1/s)
λ = (3.00*108 m/s)÷(93.1*106 s-1)λ = 3.22 m
What is the wavelength if the frequency is 93.1*106 s-1
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
Review section 5.3 AND complete # 24 on page 148
And define quantized and energy level
Due Tuesday 1-6
Assignment
1. Amplitude affects __________.
2. Shorter wavelengths = ______ frequencies
3. If a light wave has a wavelength (λ) of 3.0 * 10-7 m, what is its frequency?
Day 1 1-6
λ = c/ν
higher
brightness
= 1.0 * 1015 Hz
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=Planckh=Planck’’s s
const.const.His idea was that energy is absorbed and released in specific amountsspecific amounts.
Quantum Theory
Page 1436.626e-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
λ = c/νwavelength
speed of light
frequency
E = h E=EnergyEnergy, h=Planckh=Planck’’s s const.const.
6.626e-34 J*s
Radiant Energyis energy that travels travels through spacethrough space.
Is also known as lightlight and
electromagnetic electromagnetic radiationradiation.
Major source is…THE SUNTHE SUN
The dual nature of lightParticle??? Wave???
- Wave (continuous) as it travels through space
- Particle (quantized) as it interacts with matter
amplitude (a) - affects amplitude (a) - affects brightness, brightness, half the half the height height
wavelength (wavelength (λλ) = crest to ) = crest to crestcrest
DemocritusDemocritus’’ 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
Quantum TheoryCome up with your own:
Continuous VS. Quantized:
AND put it in your notes!
Review section 5.3 AND complete # 24 on page 148
And define quantized and energy level
Due Tuesday 1-6
Assignment
DEFINE:
atomic orbital
AND Read section 5.1 AND answer
questions 1, 2, 4, and 5 on page 132
1 definition and 4 questions
Day 6 1-15
Day 2 1-7
1. If a light wave has a wavelength of 1.0 * 108 m, what is its frequency?
2. High frequency = _____ energy and ______ wavelength
λ = c ÷ ν
3.0 HzHigh
Short
1. Amplitude affects __________.
2. Longer wavelengths = ______ frequencies
lower
brightness
3. High frequency = _____ energy and ______ wavelength
HighShort
What does it mean if something is quantized?
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
The relationship between frequency , wavelength (), and color to the energy of light: ,
Color: red = low E, violet = high E
E : many photon punchesE: big gaps between consecutive photons.
Color: red = low E, violet = high E
each color has its own energy
color = type of light
Neils BohrTried to explain why
each element has its own unique (bright) (bright) lineline spectrumspectrum. He studied HH.Using previous discoveries-
Bohr hypothesized that an atom’s electrons are located in specific energyspecific energy levelslevels. Each energy level, aka orbitorbit or shellshell is a set distance from the atom ’s nucleusnucleus. …
Atomic Emission Spectra
… Electrons jumpjump or fallfall from one energy level to another, while simultaneously gaining or losing energyenergy. Electrons are not permitted to stop betweenbetween energy levels.
Neils Bohr… Each energy
level, aka orbitorbit or shellshell. Is a set distance from the atom’s nucleusnucleus. …
Bohr’s Hypothesis•In the line spectrum of an In the line spectrum of an atom, Bohr saw specific atom, Bohr saw specific colorscolors..
•Each specific Each specific colorcolor has a has a specific specific energyenergy..
•That specific amount of That specific amount of energyenergy is related to a is related to a specific specific distancedistance from the from the nucleus.nucleus.
Who demonstrated photons can move electrons?
ComptonAHHHH!
complete # 24 on page 148
And define quantized and energy level
Assignment due NOW
DEFINE atomic orbital
AND answer questions 1, 2, 4, and 5 on
page 132
3 definitions and 5 questions