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The _________ an electron falls the ________ energy released. day 3 12-15.

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Presentation on theme: "The _________ an electron falls the ________ energy released. day 3 12-15."— Presentation transcript:

1 The _________ an electron falls the ________ energy released. day 3 12-15

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3 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

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

5 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)

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

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

8 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!

9 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

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11 Clear your desk except for your review. day 4 12-16

12 Light acts as a: wave as it … particle as it … day 5 12-19

13 How do we know that light is made up of particles? day 5 12-19

14 The energy of green light compared to that of red light is ___________. day 5 12-19

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

16 Electromagnetic Spectrum h a

17 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

18 λ = c/ν wavelength speed of light frequency

19 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

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

21 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

22 Stop and summarize

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

24 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 1436.626e-34 J*s

25 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

26 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

27 Read / review section 5.3 AND complete #s 19-24 on page 148 Assignment

28 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? higher brightness 1.0 * 10 15 Hz Day 1 12-21

29 Day 3 1-3 1. 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

30 Day 3 1-3 λ = c/ν wavelength speed of light frequency

31 Day 3 1-3 E = h Energyh=Planck’s const. E=Energy, h=Planck’s const. 6.626e-34 J*s

32 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

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

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

35 1. Amplitude affects __________. 2. Longer wavelengths = ______ frequencies lower brightness Day 3 1-3 3. High frequency = _____ energy and ______ wavelength 4. How can electrons move from one energy level to another? They must… High Short

36 Energy Source Absorbed Energy Energy Released

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

38 Democritus’ atom Quantized Matter:Energy:Plank

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

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

41 Continuous: VS. Quantized: Digital thermometer Liquid thermometer

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

43 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:

44 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

45 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

46 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

47 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

48 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

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

50 3. If a light wave has a frequency ( ν ) of 3.0 * 10 15 Hz, what is its wavelength? 1.0 * 10 -7 m Quantum Theory

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

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

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

54 Radiant Acrostic RADIANTRADIANT

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

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57 # 3 Cosmic, gamma, x-rays, UV, vis. vis., IR, microwaves, TV, radio

58 h a

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

60 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

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

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

63 Continuous: VS. Quantized:

64 Radiant Acrostic RADIANTRADIANT

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

66 Electromagnetic Spectrum h a


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