1. Light and Optics January 5-21 Miss Sunderland HPS

2. Light Sources There are two types of light Natural- still happen if people didn’t exist Constructed- Man made Is the moon a light source?

6. Rectilinear Propagation Light Spreads out in all directions from the source The light moves in straight lines and reflects off walls, doors, floors, desks etc. Everything you can see reflects light to some level

7. Shadows When an object blocks light it creates a shadow. Shadows have two parts, the umbra and the penumbra. The dark part of the shadow is called the umbra, it blocks the most light The lighter fuzzier part of the shadow is called the penumbra, it is caused by some light not being blocked

8. Shadows 2

9. Shadows When the sun is LOW in the sky there are long shadows. Early morning and late evening- why does this happen?

10. Opaque, Transparent, Translucent Matter can be classified in three different ways, according to how light moved through it.  Opaque- no light can pass through  Transparent- all light can pass through  Translucent- some light can pass through

12. Refraction When light passes from one medium (or material) to another it can bend the beam. This is called refraction. When you view an object in another medium (for example water) it appears to be where it is not. This is an optical illusion. Remember The Hatchet

14. Refraction 2 Sometimes objects appear “broken” when viewed passing through two different mediums.

15. Lenses Vs. Mirrors Lenses -can be transparent or translucent - Refract light Mirrors -are opaque -reflect light -

16. Lenses and Mirrors Both create an illusion Both can be convex or concave Both change how an image appears The focal point is where the rays meet after being reflected or passing through the lens.

17. Convex Lenses Convex – the lens is thicker in the middle - the rays of light come together - the object appears smaller - the object sometimes flips upside down - can be single or compound - called converging lens

18. Concave Lens Concave – the lens is thinner in the middle - the rays of light spread out - the object appears larger - can be single or compound - called diverging lens - image is often blurry and out of focus

19. Convex & Concave

22. Electromagnetic Radiation The sun gives off more then just visible light. It gives off many different waves. These all travel in straight lines. This is known as Rectilinear Propagation. These waves travel at different wavelengths.

23. Wavelength & EM Spectrum

24. Spectrum of Light

25. Rainbow We can use a prism to split white light into a spectrum of all visible colours. This is also known as a RAINBOW R- red* red has the highest wavelength O- orange Y- yellow G- green B- blue I- indigo V- violet* purple has the lowest wavelenth

26. Light Spectrum What appears to be “white” light is actually a combination of ALL visible colours What appears to be “black” is actually the lack of all colours

27. Wavelength & EM Spectrum

28. Why something is that colour An object appears a certain colour because it reflects that colour in the visible spectrum of light. This is what your eye picks up. The object absorbs all other colours.

29. Colour Subtraction Normally we see objects with all the visible spectrum available. What happens when we view objects in a coloured light? (ex: green light)

30. Subtracting Light Usually colours on the opposite side of the colour wheel cancel each other out. They absorb that colour. Why?

31. Where is colour subtraction used?

32. Photography Modeling Makeup Theatre

33. Why Opposites? The colour absorbs the most and reflects the least (remember no reflection = black) Why doesn’t this always work? - Printers and dyes use many colours and hues combined to form colours.

34. The Eye

35. Questions about the eye. Using what you know about lenses, refraction, reflection and absorption make a hypothesis about how the three parts of the eye work.  Lens & Cornea  Aqueous & Vitreous humor  Retina

36. The eye has many different parts, this is how it all works  Light from a source hits an object  The object absorbs most light and reflects the rest  The light hits the cornea and is slightly refracted  The light hits the aqueous humor and is slightly refracted  The light passes through the lens and is flipped upside down  The light passes through the vitreous humor and is refracted

37. 7. Light hits specific cones and rods 8. Rods (more numerous & sensitive about 120 million) are excited and send signal through the optic nerve to the brain to tell where and the intensity the light is coming from 9. Cones (less numerous, 7-9 million, 3 types red, green & blue) are excited by different colours and based one which ones are excited, send signal through the optic nerve to the brain to tell the colour of light 10. The brain collects all the signals and interprets them (by flipping them right side up and determining placement, colour and distance).

39. Other Parts of the Eye The Eyelashes- Keep dust and other particles out of the eye The Tearducts- help moisturize the eye The Iris- the muscle that allows different amounts of light into the eye The Retina- the covering of cones and rods on the back of the eyeball

40. Colour Blindness

42. Nearsighted Myopia

43. Far Sighted

44. Animal Vision

45. Black Light How does Black light Make things Appear?

46. Infrared Vision

47. Important reminder The image you see when looking through a lens or in a mirror is NOT the real thing. It is called a virtual image.

48. Optical Illusions Sun DogsReview Mirror

50. Which central circle is larger?

51. Who do you see?

52. Assignment Objectives: Explore properties and applications of optics-related technologies, including concave and convex mirrors and lenses. [SI, TPS] Evaluate the impact of electromagnetic radiation-based technologies on self and community. Goal: Explore different light and vision technology and how it affects our society.  Choose a technology  Create questions you would like to know about this technology. Using blooms taxonomy make sure at least 3 questions are upper level.  Use books, internet, video and other resources to learn about this technology and answer your questions.  Create a presentation to tell others about the technology.

53. marking 1234 Questions- Created less then 3 questions of any type -created less then 5 questions - none higher level -Created at least one higher level question -Created at least 5 questions -Created at least 3 higher level questions Research-very limited data, generalizations -discrepancies -misinformation -limited to very basic data -missing some important details -some discrepancies /misinformation -answers the questions -factual -very few gaps -answers the questions with details -links to other technologies Presentation-brief, doesn’t cover material -sloppy & poor spelling -brief, covers material basically -Poor spelling & limited evidence of effort -Poor order/flow -covers material -good spelling & effort is evident - Flows well & easy to view -covers material with detail and innovation -effort in spelling & editing -easy to view Sources-none listed and not apparent any are used -attmpted listing -may have used one or more -Listed with few mistakes --used at least 2 -listed and used multiple sources (3+)

54. Example Technology: Lasik Eye Surgery Questions:  What is Lasik Surgery? (knowledge)  What are the risks of this surgery? (comprehension)  Where can you get this surgery? (knowledge)  How does this surgery compare to other methods of vision correction? (analysis)  Is lasik surgery right for me? (evaluation)  Where might eye surgery be going in the future? (synthesis) Sources: Presentation: http://prezi.com/c32w14exxuct/laser-eye-surgery/

55. Blooms Taxonomy