Day 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 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 Energy travels through space is energy that travels through space. light Is also known as light and electromagnetic radiation electromagnetic radiation. Major source is… THE SUN

Radiant Energy… Sun’s radiant energy is the result of nuclear fusion. Nuclear fusion – light nuclei combine to form heavier nuclei Fission vs. fusion?

The dual nature of light Particle??? 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 light Particle??? Wave??? - Wave (continuous) as it travels through space - Particle (quantized) as it interacts with matter

Electromagnetic Spectrum ordered sequence light electromagnetic radiation The ordered sequence of all types of light or electromagnetic radiation.

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- High energy, bends more, inside of rainbow, 400 nm R O Y G B I V Red- Low energy, bends less, outside of rainbow, 700 nm

The energy of green light compared to that of red light is ___________.

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

Read section 5.3 and answer #s on page 148 – due Tuesday Assignment

Light acts as a: wave as it … particle as it … USE YOUR NOTES!!! Day

Read section 5.3 and answer #s on page 148 – due before you leave today Assignment

Electromagnetic Spectrum h a

amplitude (a) - affects brightness, half the height Frequency (ν) = number of crests passing a point in a period of time h = height, from crest to trough speed (c) = distance per unit time wavelength (λ) = crest to crest

λ = c/ν wavelength speed of light frequency

λ = c ÷ ν λ = wavelength c = speed of light = 3.00 * 10 8 m/s ν = fequency (s -1, Hz, 1/s) λ = (3.00*10 8 m/s)÷(93.1*10 6 s -1 ) λ = 3.22 m What is the wavelength if the frequency is 93.1*10 6 s -1

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

Can all light be described as continuous The energy of waves is continuous, 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 * m, what is its frequency? Day λ = c/ν higher brightness = 1.0 * Hz

Each color has its own energy And the energy changes with heating Quantum Theory … - quanta

Max Planck energy - related the frequency of light to its energy with the following: E = h Energyh=Planck’s const. E=Energy, h=Planck’s const. specific amounts His idea was that energy is absorbed and released in specific amounts. Quantum Theory Page e-34 J*s

specific amounts quantum quanta atoms His idea was that energy is absorbed and released in specific amounts. He called one piece, package, or bundle of energy one quantum. Bundles of energy were called quanta. He applied his quanta ideas to energy changes in atoms: Quantum Theory

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

λ = c/ν wavelength speed of light frequency

E = h Energyh=Planck’s const. E=Energy, h=Planck’s const e-34 J*s

Radiant Energy travels through space is energy that travels through space. light Is also known as light and electromagnetic radiation electromagnetic radiation. Major source is… THE SUN

The dual nature of light Particle??? Wave??? - Wave (continuous) as it travels through space - Particle (quantized) as it interacts with matter

amplitude (a) - affects brightness, half the height wavelength (λ) = crest to crest

Democritus’ atom Quantized Matter:Energy:Plank

Continuous: VS. Quantized: Height by step or rung Height on slide or ramp

Continuous: VS. Quantized: Ice cream scoops Soft-serve ice cream

Quantum Theory Come 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 definition and 4 questions Day

Day If a light wave has a wavelength of 1.0 * 10 8 m, what is its frequency? 2. High frequency = _____ energy and ______ wavelength λ = c ÷ ν 3.0 Hz High Short

1. Amplitude affects __________. 2. Longer wavelengths = ______ frequencies lower brightness 3. High frequency = _____ energy and ______ wavelength High Short

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 punches E  : big gaps between consecutive photons.

Color: red = low E, violet = high E each color has its own energy color = type of light

Neils Bohr (bright) line spectrum H Tried to explain why each element has its own unique (bright) line spectrum. He studied H. specific energy levels orbitshell nucleus Using previous discoveries- Bohr hypothesized that an atom’s electrons are located in specific energy levels. Each energy level, aka orbit or shell is a set distance from the atom’s nucleus. …

Atomic Emission Spectra

jumpfall energy between … Electrons jump or fall from one energy level to another, while simultaneously gaining or losing energy. Electrons are not permitted to stop between energy levels. Neils Bohr orbitshell nucleus … Each energy level, aka orbit or shell. Is a set distance from the atom’s nucleus. …

Bohr’s Hypothesis In the line spectrum of an atom, Bohr saw specific colors.In the line spectrum of an atom, Bohr saw specific colors. Each specific color has a specific energy.Each specific color has a specific energy. That specific amount of energy is related to a specific distance from the nucleus.That specific amount of energy is related to a specific distance from the nucleus.

Who demonstrated photons can move electrons? Compton AHHHH!

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 definitions and 5 questions