Physics 1230: Light and Color Ivan I. Smalyukh, Instructor

1. Office: Gamow Tower, F-521 • Email: • ivan.smalyukh@colorado.edu • Phone: 303-492-7277 • Lectures: • Tuesdays & Thursdays, • 3:30 PM - 4:45 PM • Office hours: • Mondays & Fridays, • 3:30 PM – 4:30 PM • TA: Jhih-An Yang • jhihan.yang@colorado.edu Physics 1230: LightandColorIvan I. Smalyukh, Instructor Class # 2

2. Using iClickers • Everyday: swap clicker code to DC • Wait for 1st clicker question to open • Hold down On/Off Switch 4 seconds • Flashing blue light: hit D C • Type in Answer. you’re set for rest of class period • DO NOT TURN OFF CLICKER FOR CLASS (o.w. repeat above for any new clicker question)

3. A Light-ning Blitz through the course material Let’s see some of the major things we’ll cover in the class.

4. Light rays and what we “SEE” Straight-line paths and what enters the eye.

5. Electromagnetic spectrum c = f l Wavelength Frequency Speed of light

6. Electromagnetic waves can have any wavelength Scientific notation is useful!

7. Shadows, reflection, refraction – Ch. 2

8. Lenses and mirrors – Ch. 3

9. Lenses and mirrors – Ch. 3 Precise mathematics let’s you DESIGN lens systems.

10. Photography – Ch. 4 Image recording - digital

11. The Eye – Ch. 5 Visual systems in other creatures.

12. Optical instruments – Ch. 6 Telescopes

13. The “Very Large Array” ‘near’ Socorro, NM.

14. Optical instruments – Ch. 6 Microscopes Robert Hooke’s circa 1660 Modern laser confocal

15. Your eyes can play tricks on you – Ch. 7

16. Visual Processing – Ch. 7

17. Visual Processing – Ch. 7

18. Color – Ch. 9

19. Color perception – Ch. 10

20. Color perception – Ch. 10 The sum of the two number is: A) 18 B) 20 C) 23 D) 25

21. Scattering & Polarization – Ch. 13

22. Holography and Lasers – Ch. 14 & 15

23. Break for 7th inning stretch. Favorite answers: We want to understand these things Because… Something to ponder during the stretch: WHY (and how) do we see things? Because there is LIGHT… Because we have EYES… Because creatures that see tend to survive…

24. First goals of the course: Understand enough about light to be able to talk about it. Develop our first model for how light behaves and how we SEE things.

25. Disappearing glass rods… http://www.youtube.com/watch?v=pNWCB_GoQA4 http://www.youtube.com/watch?v=7hOZJL_bEPQ

26. Cloaks of invisibility? http://www.youtube.com/watch?v=mcPzCb7TlZ8&NR=1

27. Please, make a list with : What do you already know about light? Spectrum Wave and particle properties Source of energy momentum Fast speed Straight line unless it interacts

28. Seeing everything in terms of rays Light rays are invisible unless they enter directly into our eye or are scattered bysmoke, fog or some object into your eye! Laser MANY reflected rays comefrom all parts of Alex, includinghis nose - a diffuse object Flashlight Light bulb Incident ray from a light bulb Bob sees Alex's nose because a reflected light ray enters Bob's eye!

29. Rays bounce when they reflect off a mirror or shiny surface • This is called specular reflection. • How is it different from • diffuse reflection? Mirror

30. To understand light better we need to know about Waves • Electric fields • Magnetic fields • Light is an ‘electromagnetic wave’ E B

31. There are two types of charge • There is only one type of charge • There are more than two types • None of the above. QUALITATIVE things about electric forces • Like charges attract • Like charges repel • Opposite types repel • Depends on the situation. And opposites attract

32. Coulomb’s Force Law: Depends on the charges QUANTITATIVE statement: Q r distance Constant of nature. q What is the force that q feels from Q?

33. You are given three numbers, a, b, and c. True or false: The combination of numbers A question: is always equal to: A) TRUE B) FALSE Experiment: Try some actual numbers, like a=2, b=3, c=4 and test it.

34. You are given four numbers, a, b, c, and d. Which of these are valid ways to rewrite A) B) C) D) E) Experiment can be valuable here too… All of the above None of the above

35. Coulomb’s Force Law: Depends on the charges QUANTITATIVE statement: Q r distance Constant of nature. q What is the force that q feels from Q?

36. Coulomb’s Force Law: Useful to rewrite things: Which is another way to write this force law? A) B) C) D) E) None of these All of these

37. Coulomb’s Force Law: The universe divides into two parts: Property of the local THING, say YOU. Properties of the rest of the universe. We Say: ELECTRIC FIELD due to the rest of the universe.

38. The force felt by q … • Can still be F=qE • Cannot be F=qE • MAY be F=qE if the charges are in a line. • Something else happens. Suppose we have 3 charges: Q1 Q2 r1 r2 q

39. ELECTRIC FIELD due to the rest of the universe. We Say that charges feel a force: Electric Fields The charge value. Properties of the rest of the universe.

40. Magnets come with only a north pole • Magnets come with only a south pole • Magnets come with both a north and south pole. • Depends upon the type of magnet. What do you already know about magnetism? GUESS WHAT: The universe produces Magnetic Fields too. • Like poles attract • Like poles repel • Opposite poles repel • Depends on the situation.