1. 5.3 physics and quantum mechanics

2. Vocabulary lets talk the talk as we walk the walk, and meet the people in this neighborhood the height of the wave from ‘0’ to the crest Amplitude : the height of the wave from ‘0’ to the crest Wave Length : represented by the Greek lambda ( λ ) an upside down script Y of sorts The distance between the crests of the waves. Surfs up dude! Frequency: represented by the Greek nu ( V ). A “v” of sorts the number of wave cycles to pass a given point per unit of time. time. SI unit of frequency, cycles per second Hertz, (Hz) the SI unit of frequency, cycles per second, can be expressed as a reciprocal second (s -1 ) second = s / 1,reciprocal = 1 / s

3. w Frequency ν (s -1 ) |←1 s→| ―――――――――――――――――――――――――――― ↕ ↕ Amplitude ← wave- → length High frequency Low frequency ↓ ↓ crest 0

4. Wavelengths and light frequency are inversely proportional: as one increases the other decreases The product of frequency and wavelength always equals c a c onstant c= the speed of light! c Constant c = λ V ( as wavelength increases frequency decreases so C remains the same.) λ Wavelength λ= c / v v Frequency v = c / λ Light is made up of Electromagnetic radiation, includes radio waves, x-rays, and gamma rays. All electromagnetic waves travel in a vacuum at a speed of 2.998 X 10 8 m/s

6. What color in the visible spectrum has the longest wavelength?

7. white Sunlight seems white but it is really made up of many different frequencies (colors) of light, a continuous range of wavelengths. The specific color of light depends upon its frequency. If you pass light through a prism it will break the light into each frequency, making a rainbow. The colors of the rainbow depend upon the specific frequencies of the particular light. warmer colors (red) low energy(700 nm)the shorter The longer frequencies are the warmer colors (red) low energy(700 nm) while the shorter frequencies are the cool colors (violet) high energy, (380 nm)

8. Drops of water act as prisms, as sunlight passes through them they make rainbows. The colors of the rainbow are always in the same order. My physics teacher in high school Mr. Roy G. Biv made us memorize them. R red O orange Y yellow G green B blue I indigo V violet

10. Atomic Spectra Neon lights fill our nights with color. Hollow glass tubes filled with gasses have electricity passed through them. When “excited” by an electric current the electrons in these gasses, jump to, then fall back from higher energy levels, while they fall back they give off their “quantum” of energy causing the bright colors of these lights. Each gas has a characteristic color, not all the gasses are neon. We just call them neon lights!

11. If the light emitted by the spectrum is seen as bands of colors that are not touching it is referred to as discrete bands. Each band identifies a specific frequency contained in that light. These colors show the spectrum identifying the frequencies, the bands that are missing show that these frequencies are not present in that light. These discrete bands of light give the atomic emission spectrum of the element. Each discrete line in an emission spectrum corresponds to an exact frequency of light emitted by a specific atom. I II I I III III I I II An atoms atomic spectrum is the atoms fingerprint

12. www.astro.uiuc.edu/~kaler/sow/spectra.html Go to this site and see some great examples of electromagnetic spectra! S P E C T R A We know what the stars are made of, know of their structures and their lives, only because we are able to observe and analyze their spectra. Unbroken starlight allows us to admire a star's external characteristics; its spectrum allows us to look into its very soul. This site, closely coupled to The Natures of the Stars, provides an introduction to the spectra of stars and allied celestial objects. Here we examine the principal way in which astronomers have learned so much about the stars. "Spectra" is embedded with links that will take you back to the appropriate parts of "The Natures of the Stars."The Natures of the Stars

13. H Ground state the lowest possible energy of the Electron. The –e principle quantum # Absorption of energy raises the –e to an excited state. n = 2,3,4,5,6,7. A quantum of energy is emitted as the electron falls back to its ground state. this abrupt release of energy Released as the –e drops, the quantum Causes an electronic emission, called an Electronic transmission.

14. The light emitted by an-e moving from a higher to a lower energy level has a frequency directly proportional to the energy change of the falling –e. n=2 to n=1 is a specific frequency. N=7 to n=6 is a different frequency. ¦--¦ n=7 ¦--¦ n=6 ¦--¦ n=5 ¦--¦ n=4 ¦ ¦ ¦--¦ n=3 ¦ ¦ ¦--¦ n=2 ¦ ¦ the rungs on the atomic ladder are not evenly spaced ¦ ¦ the farther from the nucleus you get the closer the rungs are. ¦--¦ n=1 ¦ ¦ nucleus ¦--¦ Each transmission produces a line of specific frequency in the spectrum

15. Bohrs model was not perfect, only partially right. The quantum mechanical model solved these issues.

16. 1905 Einstein revisited Newton's idea of particles of light. He proposed the light can be described as a “quanta” of energy. These quanta behave like particles. These light quanta are called photons.

17. L. De Broglie asked…. If light behaves like waves and particles, can particles of matter behave like waves? Lets call the behavior of particles “matter waves”.

18. “Matter must move in wave like patterns!” Three years later two new jersey scientists realized that electrons reflected off of a metal surface produce curious patterns a lot like X- rays, (electromagnetic waves) confirming de Broglie’s mathematical theories! de Broglie is awarded the Nobel prize.

19. Classical mechanics describes the motion of bodies much larger than atoms. Quantum mechanics describes the motion of sub atomic particles and atoms as waves. Heisenberg Uncertainty Principle you can know where and electron is, or how fast it is traveling but you can not know both at the same time with any accuracy. Officially it states” the impossibility of knowing the velocity and position of a moving electron at the same time.”

20. Why do you think sunsets are in the red family? Think of the atmosphere as a prism, think of the light frequency. At what angle are the suns rays hitting the atmosphere? What other colors do you see in the sky at sunset?

22. Do your homework and read the book! Ask questions!