Machines and Metaphors: Clocks, Steam Engines, and Computers in Science

1. Computer Science 129 Science, Computing and Society Week 3 Chapter 2

2. GRE/GMAT WORDS • Pedant - person who orveremphasizes rules and details, makes excessive display of learning • Vacillate – to waver or to be indecisive • Capricious – subject to a whim, erratic • Engender – to cause

3. GRE/GMAT WORDS REGARDLESS -adjective 1.having or showing no regard; heedless; unmindful (often fol. by of). –adverb 2.without concern as to advice, warning, hardship, etc.; anyway: I must make the decision regardless. THERE IS NO SUCH WORD AS IRREGARDLESS

4. Chapter 2 Machines and Metaphors • Metaphor • A figure of speech in which a word or phrase that ordinarily designates one thing is used to designate another, thus making an implicit comparison, as in “a sea of troubles”

5. Chapter 2 SUPERPARADIGMS • Point of view about what is fundamental in determining what happens in the world • Driving forces for history of modern science

6. Chapter 2 SUPERPARADIGMS • Clock • Steam Engine • Computer All have inspired frameworks for science

7. Chapter 2 CLOCKS-14TH century we see weight driven clocks • Described the universe in terms of motion governed by Force like moving parts of weight driven mechanical clock • Metaphor for scientific worldview based on FORCE • All of science was focused on force

8. Chapter 2 STEAM ENGINE • Huge in end of 18th century and 19th century (1765) • Able to get power from steam • Watt style steam engines largest source of power in industrial England • Pumping water out of mines • Driving flour and textile mills

9. Chapter 2 • By the 19th Century, the Steam Engine became driving force in transportation • Became symbol of Industrial Revolution • Metaphor for scientific worldview based on ENERGY • All of science began thinking in terms of energy

10. Chapter 2 COMPUTER • Fight over who actually invented the computer • Charles Babbage created 1st Analytical Engine • Metaphor for scientific worldview based on INFORMATION • All aspects of science and society are focused on information

11. Chapter 2 • COMPUTERS USE BOOLEAN LOGIC • BASE 2 • USES 0’s AND 1’s

12. Chapter 2 COUNTING IN BASE 2 = POSITIONAL NOTATION WITH A RADIX OF 2 • 0 = 0 5 = 101 10 = 1010 15 = 1111 • 1 = 1 6 = 110 11 = 1011 16 = 10000 • 2 = 10 7 = 111 12 = 1100 17 = 10001 • 3 = 11 8 = 1000 13 = 1101 18 = 10010 • 4 =100 9 = 1001 14 = 1110 19 = 10011

13. Chapter 2 • When counting in base 2 you count up starting at zero and only use numbers that only contain a 0 or a 1. • 0,1, then you must skip 2,3,4,5,6,7,8 and 9 because they use a number other than 0 or 1. The next usable number is 10, then 11, then 100. The number 12-99 all use numbers other than 0 and 1. Study the table on the previous slide. You will need to be able to count to 10 in base 2 for the midterm.

14. Chapter 2 ALAN TURNING – 1930’s – USED BOOLEAN LOGIC • Cracked German secret code in WWII- ENIGMA • Analyzed Physics of pattern formation • Turing Test • Determined how, in theory, digital computers work

15. Chapter 2 The Turing Test • Called Imitation Game • Used to test a machine to determine if the machine is “intelligent” • Measures the performance of a machine against that of a human being

16. Chapter 2 How The Turing Test Works • Machine and human placed in 2 rooms • Another person (the interrogator) is in a third room and cannot directly communicate with other person or machine • The interrogator asks questions of the machine and person questions via a text terminal

17. Chapter 2 • Based on the answers given, the interrogator must try to distinguish between person & machine • If the interrogator cannot distinguish the two, the machine is assumed to be intelligent

18. Chapter 2 • You can ask any type of question. What the interrogator is looking for is the human answer…not the right answer. • What is ultimately tested is how good the programmer is…whether or not they wrote a good program to respond to the interrogator. • This was the beginning of artificial intelligence.

19. Chapter 2 • ARTIFICIAL INTELLIGENCE • a system that perceives its environment and takes actions which maximize its chances of success • EXAMPLES: • Chess games • Facial recognition software • Fingerprint analysis

20. Chapter 2 TURING MACHINE • Turing Machine is like a typewriter • He wanted to find a machine that, using some guaranteed method, could figure out anything • This method needs a set of specific instructions (called algorithm)

21. Chapter 2 • This device needed a few things • To read long strip of paper • To write on paper (long strips divided into squares) • An erasing key to remove existing marks on square • Paper can move forward & backwards one square • Be able to change states

22. Chapter 2 • Think of states like your keyboard. There is a set of instructions for each key and that would be one state • When you hold down the shift key, there are a whole new set of instructions for the keys. This would be another state. • The machine could have an infinite number of states…or an infinite number of sets of instructions.

23. Lasersfrom howstuffworks.com • CD players • DVD players • Dental drills • High speed metal cutting machines • Tattoo removal • Scar removal • Skin resurfacing (for wrinkles and discoloration) • Hair replacement • Eye surgery

24. Lasers • How are they different from a flashlight? • Lets look at the atom • Only 110 different kinds of atoms in the universe • Everything we see is made up of these 110 atoms in an unlimited number of combinations. • How these atoms are arranged and bonded together determines whether the atoms make up a cup of water, a piece of metal, or the fizz that comes out of your soda can!

25. Lasers • Atoms have a nucleus made up of protons and neutrons and an electron cloud with electrons.

26. Lasers • Atoms are in constant motion-BROWNIAN MOTION • Atoms can be in different states of excitation. In other words, they can have different energies • If we apply a lot of energy to an atom, it can leave what is called the ground-state energy level and go to an excited level. The level of excitation depends on the amount of energy that is applied to the atom via heat, light or electricity

27. Lasers • When energy is applied, the electrons move away from the nucleus from lower energy orbitals to higher energy orbitals • When the electron returns to the lower energy orbital, it releases it’s energy as a photon, or a particle of light • All light is due to electrons changing orbits and releasing photons

28. Lasers • A laser is a device that controls the way that energized atoms release photons. • "Laser" is an acronym for light amplification by stimulated emission of radiation, which describes very succinctly how a laser works

29. Lasers • Typically, very intense flashes of light or electrical discharges pump the lasing medium and create a large collection of excited-state atoms • It is necessary to have a large collection of atoms in the excited state for the laser to work efficiently. • In general, the atoms are excited to a level that is two or three levels above the ground state.

30. Lasers • Once excited, the electron can simply relax, and in turn rid itself of some energy. This emitted energy comes in the form of photons (light energy).

31. Lasers • The photon emitted has a very specific wavelength (color) that depends on the state of the electron's energy when the photon is released. • Two identical atoms with electrons in identical states will release photons with identical wavelengths.

32. Lasers Laser Light has the following properties: • Laser light is very different from normal light. The light released is monochromatic. It contains one specific wavelength of light (one specific color). The wavelength of light is determined by the amount of energy released when the electron drops to a lower orbit. • The light released is coherent. It is “organized” -- each photon moves in step with the others. This means that all of the photons have wave fronts that launch in unison. • The light is very directional. A laser light has a very tight beam and is very strong and concentrated. A flashlight, on the other hand, releases light in many directions, and the light is very weak and diffuse.

33. Lasers • To make these three properties occur takes something called stimulated emission. This does not occur in your ordinary flashlight -- in a flashlight, all of the atoms release their photons randomly. • In stimulated emission, photon emission is organized.

34. Lasers • The other key to a laser is a pair of mirrors, one at each end of the lasing medium. • Photons, with a very specific wavelength and phase, reflect off the mirrors to travel back and forth through the lasing medium. • In the process, they stimulate other electrons to make the downward energy jump and can cause the emission of more photons of the same wavelength and phase.

35. Lasers • A cascade effect occurs, and soon we have propagated many, many photons of the same wavelength and phase. • The mirror at one end of the laser is "half-silvered," meaning it reflects some light and lets some light through. • The light that makes it through is the laser light.

36. Lasers • There are many different types of lasers. • The laser medium can be a solid, gas, liquid or semiconductor. • Lasers are commonly designated by the type of lasing material employed

37. Lasers Laser Types • Solid-state lasers have lasing material distributed in a solid matrix (such as the ruby or neodymium:yttrium-aluminum garnet "Yag" lasers). • Gas lasers (helium and helium-neon, HeNe, are the most common gas lasers) have a primary output of visible red light. CO2 lasers emit energy in the far-infrared, and are used for cutting hard materials.

38. Lasers • Excimer lasers (the name is derived from the terms excited and dimers) use reactive gases, such as chlorine and fluorine, mixed with inert gases such as argon, krypton or xenon. When lased, the dimer produces light in the ultraviolet range. • Dye lasers use complex organic dyes, such as rhodamine 6G, in liquid solution or suspension as lasing media. They are tunable over a broad range of wavelengths. • Semiconductor lasers, sometimes called diode lasers, are not solid-state lasers. These electronic devices are generally very small and use low power. They may be built into larger arrays, such as the writing source in some laser printers or CD players.

39. What You Should Know NAME THE 3 SUPERPARADIGMS OF THE LAST THOUSAND YEARS. 1. 2. 3.

40. What You Should Know

41. What You Should Know • BE ABLE TO COUNT TO 16 IN BASE 2.

42. What You Should Know What Requirements Did Turing Have For His Computational Machine? 1. 2. 3. 4. 5.

43. What You Should Know SHORT ESSAY: EXPLAIN HOW A TURING MACHINE WORKS. INCLUDE INFORMATION ABOUT STATES.

44. What You Should Know SHORT ESSAY: EXPLAIN HOW THE TURING TEST WORKS AND WHAT IS DETERMINED FROM THE OUTCOME.

45. What You Should Know What kinds of things use laser technology?

46. What You Should Know How many types of atoms are there in the universe? What two regions make up an atom? 1. 2.

47. What You Should Know What do you find in the nucleus of an atom? 1. 2. What do you find in the electron cloud of an atom? 1.

48. What You Should Know Describe an atom’s different states of excitation

49. What You Should Know Describe how light is emitted in a laser (how is a laser created).

50. What You Should Know What is the word laser an acronym for?