1. Chapter 4
Spectroscopy
Parts 1 & 2

3. Describe the process that occurs inside atoms that produces the spectra?
Energy is absorbed by the atom.
The electrons jump into higher orbits and the atom becomes “excited”.
The electrons return to their original orbits and the atom returns to the ground state.
The electrons release energy in the form of visible light.
Each quantum leap produces a specific spectral line of a certain energy (wavelength, frequency) of visible light.

4. Quantum Leaps
A quantum leap is a change of an electron from one energy state to another within an atom.
Quantum leaps cause the absorption and emission of electromagnetic radiation in which “excited” atoms release small packets of electromagnetic energy called photons.

5. Some Uses and Examples of “Exciting” Atoms (Quantum Leaps)

6. Aurora Borealis

7. Northern lights (Aurora’s) are one of nature's most beautiful manifestations of the ability of electrons to jump between quantum states

8. What Causes the Aurora
High speed energetic particles collide with atoms in Earth's atmosphere to cause the aurora. These high speed particles, which are usually electrons, originate from space, specifically from the solar wind, blowing outward from the Sun.
When the electrons from space strike an atom or molecule in Earth's atmosphere, they give one of the electrons in the atom an energy boost. In scientific jargon, the electron jumps to a higher energy level and the atom is in an excited state.

9. What Causes the Aurora
After a while, the electron in the excited atom jumps back down to its original lower energy level. It releases this energy as light causing the auroral glow. This process is the same mechanism that causes emission line spectra and aurora are in fact emission line spectra of the atoms in Earth's upper atmosphere.
The color of emission line spectra depends on the type of atom that is excited, and each type of atom produces its own unique pattern of colors. Hence, the different colors in auroral displays originate from different elements in Earth's atmosphere.

10. What Causes the Aurora
Oxygen molecules cause the green Aurora, and oxygen atoms cause the red colors. Blue auroral displays result from nitrogen molecules. Molecular nitrogen and oxygen are the most common constituents of Earth's atmosphere, so these are the most common auroral colors. Mixtures of these colors form the other colors of the auroras.

11. Northern Lights Video (3:57)

12. Did you ever wonder how we know what the universe is made of?

13. The entire article is posted near the door of the classroom if you would like to read more.

14. Star Finder Video - Fingerprints of Light (10:05) Full Video (13:50)

15. Spectroscopy is the study of the energy which is given off and absorbed when atoms go from the ground state to the excited state and back again.
Spectroscopy is often used in chemistry for the identification of substances, through the spectrum absorbed or emitted.

16. Spectroscope

17. Fireworks

18. Neon Signs

19. Light Sources – Mercury
CFL’s
The average rated life of a CFL is between 8 and 15 times that of incandescents. CFLs typically have a rated lifespan of between 6,000 and 15,000 hours, whereas incandescent lamps are usually manufactured to have a lifespan of 750 hours or 1,000 hours.
Mercury Vapor Lamp

20. Spectrum of a CFL bulb. The camera had a diffraction grating in front of the lens. The discrete images are produced by the different colors in the light, a line spectrum. An incandescent lamp would instead have a continuous band of color.

21. American and 2 Japanese Physicists Share 2014 Nobel Prize for Work on LED Lights

22. LEDs LEDs, (Light emitting diodes), are found in all kinds of devices.
They form numbers on digital clocks, transmit information from remote controls, light up watches.
Collected together, they form the illuminated screens on cell phones and television screens.
Basically, LEDs are just tiny light bulbs that fit easily into an electrical circuit. But unlike ordinary incandescent bulbs, they don't have a filament that will burn out, and they don't get especially hot.

23. LEDs LED’s are illuminated solely by the movement of electrons.
The lifespan of an LED is impressive lasting 10 times as long as a fluorescent bulb and 100 times as long as an incandescent bulb.
LED bulbs do not have toxic mercury as do CFL’s.
Due to low power requirements, it can be powered by cheap local solar power. Thus bringing the advantage of electrical devices to places that lack electrical power grids.
Currently upfront costs are higher than many consumers which to pay but costs are continuing to drop as technology improves.

24. In the future, some of the most incredible uses of LEDs will actually come from organic light emitting diodes, or OLEDs which are flexible, allowing scientists to create bendable lights and displays. (Imagine rolling your TV up like a poster and carrying it with you anywhere).

25. Lasers
You'll find them in everything from CD players to dental drills to high-speed metal cutting machines to measuring systems. Tattoo removal, hair replacement, eye surgery -- they all use lasers.

26. What else can lasers be used for?
Sharks

27. I want sharks with laser beams attached to their heads.

28. Flame Tests

29. Flame Tests
A flame test is a procedure used in chemistry to detect the presence of certain metal ions based on each element's characteristic emission spectrum.

30. ..\..\..\..\Videos\Flame Tests.wmv
Video: Flame Tests (27seconds)
..\..\..\..\Videos\Flame Tests.wmv

31. Video: Molecular Fingerprints (15 min.) Worksheet is in notebook.
..\..\..\..\Videos\World of Chemistry\Molecular Fingerprints.mpg

32. Homework
Summarize the purpose and procedure for the “Flame Test” Lab (Due tomorrow).
Chapter 4 Worksheet 3 (Due Friday).
Study Guide Chapter 4 (Due Friday).