Light and Optical Systems

Light and Optical Systems

1. Properties of Light

   • Light travels in straight lines
   • Light can be reflected
   • Light can bend/ refract
   • Light is a form of energy

2. Glare is the light reflected off of glass

3. Shadows

   • Shadows only from opaque objects, some translucent but never transparent.
   • Light cannot go through opaque objects like us, so it creates a shadow instead.
   • When an opaque object is closer to the light source, it creates a bigger shadow because it is blocking more light.

4. Light Interactions

   • Transparent
     • light rays travel straight through these objects and that is why we can see through them clearly.
   • Translucent
     • some light can pas through, not all the light rays- this is why we sometimes see through clearly but not much, might be blurry
   • Opaque
     • light DOES NOT pass through these types of objects so we cannot see through them and they make shadows instead.
     • Opaque objects like like pencils are non-luminous because they do not produce their own light, unlike a flashlight or the sun.

5. When a light source is closer to your eyes, it is really bright because most of the rays goes into our eyes. When the light source is farther away from your eyes, it is not as bright because fewer rays hit your eyes because the distance

6. Early Light Ideas

   • Pythagoras
     • thought light was beams and thought the light beams came out of our eyes
   • Euclid
     • angle of reflection, the incoming beam and reflected beam are the same angle
   • Al-Haytham
     •  accurately describes vision, light reflects off objects and into our eyes
   • Isaac Newton
     • figured out the different frequencies of light by shining it through a prism.
   • Albert A. Michelson
     • discovered the speed of light.

7. Concave Mirrors

   • Curve inward
   • Collect light
   • Obey the Law of Reflection
   • Rays head to a common point, the FOCAL POINT
     • Collecting light and bringing it all into a single point. Where all the reflected light rays intersect. 
   • Ex. Flashlight, telescope, car headlights.
   • If the object is far from the focal point of the mirror, the reflected rays form an upside down image, which is much smaller than the object.
     • But when the object is closer to the focal point, the image becomes larger than the actual object.
     • If the object is between the focal point and the mirror, it appears right side up and bigger.

8. Convex Mirrors

   • Curves outward
   • Spreades light outwards
     • Opposite of concave mirror.
   • Reflected images appear smaller than they are
   • Ex. car side mirrors, security mirrors, etc
     • Because car mirrors say "Objects in the mirror are closer than they appear" the reflected image is smaller because they reflect more scenery.
   • Convex mirrors reflect parallel rays as if they are coming from behind the mirror

9. Waves

   • Wavelength
     • The distance from one crest to another crest- the length between the crests.
   • Amplitude
     • The height of a wave from rest to crest position.
   • Frequency
     • The number of times the wave goes on in a certain amount of time
   • The Electromagnetic Spectrum
     • Hi
     • 1. Radio Waves
       • Used for radios, communication. These are the longest wavelengths. 
     • 2. Microwaves
       • -used to heat up food -shorter than radio waves -carry more energy than radio waves -make water particles in food vibrate
     • 3. Infrared Waves
       • -we can't see them -felt as heat -special equipment to actually see them
     • 4. Ultraviolet Waves
       • -carries more energy than visible light -can burn the skin  -skin risks like cancer -most rays absorbed by ozone layer -can be protected by sunblock
     • 5. Visible Light Waves
       • Natural Sources of Visible Light: -stars -combustion -Bioluminescence -Chemiluminescence
       • Artificial Sources of Visible Light -Incandescent Light -Fluorescent Light -LED (light emitting-diodes) Light
     • 6. X-Rays
       • -high energy radiation -useful for medical imagine -can see your bones
     • 7. Gamma Rays
       • -high energy radiation -used to kill cancer cells -
   • form of energy
   • travel out in all directions

10. Eyes ?️?️

    • Outer Parts
      • Cornea
      • Sclera
      • Optic Nerve
    • Fluid Parts
      • Aqueous Humor (Front)
      • Vitreous Humor (Rear)
    • Front Parts
      • Iris
      • Pupil
      • Lens
      • Ciliary Muscle
    • Rear Parts
      • Retina
        • Rod Cells
        • Cone Cells
        • Blood Vessels
      • Fovia
      • Blind Spot
    • Camera
      • Controls Light
        • Diaphragm
        • Aperture
      • Allows Light to Enter
        • Shutter
      • Collects light
        • Double Convex Lens
      • Stores Image
        • Colour Film
        • Black and White Film

11. Colours of Light

    • Primary Colours
      • Green
      • Blue
      • Red
    • Secondary Colours
      • Yellow
        • Green + Red
      • Cyan
        • Blue + Green
      • Magenta
        • Red + Blue

12. Sources of Light

    • Natural
      • Stars
      • Combustion
      • Bioluminescence
      • Chemiluminescence
    • Artificial
      • Incandescent
      • Fluorescent
      • LED

Bilder und Dateien der Mindmap