The _________ an electron falls the ________ energy released. day

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

Clear your desk except for your review. day

Light acts as a: wave as it … particle as it … day

How do we know that light is made up of particles? day

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

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

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

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

Read / review section 5.3 AND complete #s on page 148 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? higher brightness 1.0 * Hz 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

Day λ = c/ν wavelength speed of light frequency

Day 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

1. Amplitude affects __________. 2. Longer wavelengths = ______ frequencies lower brightness Day High frequency = _____ energy and ______ wavelength 4. How can electrons move from one energy level to another? They must… High Short

Energy Source Absorbed Energy Energy Released

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

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

Continuous: VS. Quantized: Digital thermometer Liquid thermometer

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

Light energy hits the electrons in metal- the light must be powerful enough. The electrons become excited, and they jump out of the metal. Electrons in the metal absorb the energy. Quantum Theory Quanta’s Ability:

The electrons fall down again, and create a spark or current. Examples: The luster of a shiny metal, Photoelectric cells (solar power) The electrons become excited, and they jump out of the metal. Quantum Theory

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

DEFINE: energy level AND atomic orbital AND Read section 5.1 AND answer questions 1, 2, 4, and 5 on page definitions and 4 questions Day

1. Amplitude affects __________. 2. Shorter wavelengths = ______ frequencies higher brightness Quantum Theory

3. If a light wave has a frequency ( ν ) of 3.0 * Hz, what is its wavelength? 1.0 * m Quantum Theory

How long did we view matter as continuous? Energy? Quantum Theory

What did scientists observe that led them to view light as quantized? Quantum Theory

How is energy related to frequency? Frequency to wavelength? And so energy to wavelength? Quantum Theory

Radiant Acrostic RADIANTRADIANT

Practice Problems #s 5- 7 on page 143 AND READ section 5.1 and complete #s 8-12, and 14 on page 145

# 3 Cosmic, gamma, x-rays, UV, vis. vis., IR, microwaves, TV, radio

h a

radio, _______, radar, IR, vis. vis., ___, X-ray, gamma, cosmic _________ & Long ________ & Short!

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

Democritus’ atom Continuous: VS. Quantized: Aristotle’s matter

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

Continuous: VS. Quantized:

Radiant Acrostic RADIANTRADIANT

Radiant Energy… Nuclear fusion – light nuclei combine to form heavier nuclei The dual nature of light?

Electromagnetic Spectrum h a