LIGHT, COLOUR GR9 by Lizelle Swanepoel https://padlet.com/lizellexs/h5hslcbahs10rtql en-us 2022-05-09 11:49:48 UTC 2026-05-26 11:25:18 UTC hello@padlet.com https://padlet.net/icons/png/1f526.png NOTES - LIGHT lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543970 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543970 LENSES - brief overview lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543971 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543971 COLOUR NOTES lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543973 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543973 SIMULATIONS - ALL OPTIC PHENOMENA lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543974 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543974 NATURE OF LIGHT: rule 1 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543975 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543975 Rule 2 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543976 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543976 Rule 3 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543977 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543977 The nature of light lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543978
  • An object can be seen when the light that is reflected or emitted by an object enters the eye.  
  • If no light enters the eye, the absence of light is interpreted as darkness and the object appears to be black. 
  • Light travels in straight lines (unless acted upon by a surface or force).
    • ]]>     2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543978     Rays and beams of light lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543980 A ray is a straight line with an arrow representing the direction in which light is travelling.
     
    A beam is a stream of light energy which is represented by a number of rays. 
    ]]>     2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543980     Pinhole camera lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543981 A simple pinhole camera can be made out of a shoe box painted black inside. Cut square holes out of each end of the box. Fix a sheet of aluminium foil over one hole and make a small, round hole (aperture) in the foil with a pin. Paste a piece of tracing paper over the other hole to serve as a screen. Aim the aperture at an object and observe the image produced on the tracing paper.  

     
    ]]>     2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543981     PINHOLE CAMERA lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543982 What characteristic of light explains why an inverted image of an object forms in a pinhole camera?]]> 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543982 UMBRA VS PENUMBRA lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543983 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543983 Transmission, absorption and reflection lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543986
    Light falling on an object can be transmitted (pass through), absorbed and/or reflected.  
    ]]>     2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543986     lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543987 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543987 ABSORPTION, REFLECTION & TRANSMISSION OF LIGHT lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543988 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543988 2 TYPES OF REFLECTION lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543989 SPECULAR VS DIFFUSE

    KNOW:

    Laws of reflection

    1.  The angle of incidence is equal to the angle of reflection.
    2. The incident ray, normal and reflected ray, at the point of incidence (B) all lie in the same plane.

    ]]>     2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543989     Properties of a plane (flat) mirror image lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543990 1.       Laterally inverted. 
    2.       Upright. 
    3.       Same size as object. 
    4.       As far behind the mirror as the object is in front.  
     
    ]]>     2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543990     APPLICATIONS OF MIRRORS AND REFLECTION lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543991 PERISCOPES!]]> 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543991 HOW A PERISCOPE WORKS lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543992 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543992 ABSORPTION VS REFLECTION OF LIGHT lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543993
  • Many objects contain atoms capable of either selectively absorbing, reflecting or transmitting one or more frequencies of light. 
  • The frequencies of light that become transmitted or reflected to our eyes will contribute to the color that we perceive.
    • ]]>     2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543993     OPTICS (LIGHT) lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543995 LIGHT = ELECTROMAGNETIC WAVES
    Consists of 2 perpendicular waves:
    • a vertical electric field and 
    • a horizontal magnetic field, 
    • in phase with each other. 
    ]]>     2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543995     lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543996 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543996 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543997 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543997 THE WAVE EQUATION: lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543999
    v = f.λ                        where, v is speed
                                                    f is frequency
                                                    λ is wavelength

    HOW TO DERIVE THE WAVE EQUATION:
    We know:                speed = distance / time
    For a wave:             speed = wavelength / time
                                                 = λ / T
                                                 = λ x 1/T
                                                 = λ x f
                                              v = fλ]]>     2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175543999     EM SPECTRUM lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544000
    Radiation of all frequencies travels at the same velocity through space. The speed of light in vacuum, c, is equal to 3 x 108 m.s−1.

    • The wavelength and frequency of these waves can be calculated using the wave equation,
    • c = f λ 
    • where c is the speed of light = 3 x 108 m.s−1
      f is the frequency measured in hertz (Hz)
      λ is wavelength measured in metres (m)
    ]]>     2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544000     Refraction lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544001 Real vs apparent depth]]> 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544001 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544002 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544002 T.I.R. (total internal reflection) lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544003
  • TOTAL INTERNAL REFLECTION = the complete reflection of a light ray reaching an interface with a less dense medium when the angle of incidence exceeds the critical angle.
  • CRITICAL ANGLE = the size of an incident angle that produces a refracted angle of 90°.
    • ]]>     2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544003     Uses of TIR - Optical fibers lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544004 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544004 TIR - APPLICATION IN MIRAGES lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544005 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544005 EXERCISE ON REFRACTION AND T.I.R lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544007 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544007 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544008 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544008 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544009 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544009 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544010 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544010 Some more definitions lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544012
  • Refractive index = the ratio of the speed of light in a vacuum to its speed in a refractive material, where bending of a ray of light occurs when passing from a medium into another with different density.
  • Optical density = a measure of the refracting power of a medium.
  • Total internal reflection = the complete reflection of a light ray reaching an interface with a less dense medium, when the angle of incidence exceeds the critical angle.
  • Critical angle = The angle of incidence where the angle of refraction is 90°. 
  • Normal = the line that is perpendicular to the plane of the surface.
  • c = 299 792 458 m.s-1 ≃ 3 x 108 m.s-1

    • ]]>     2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544012     REFRACTION - EVERYDAY EXAMPLES lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544013 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544013 APPLICATION OF REFRACTION: MAGNIFYING GLASS VS TORCH lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544014 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544014 TV CAMERA LENSES lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544015 Why so large?]]> 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544015 HOMEWORK lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544016 LIGHT WORKSHEET]]> 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544016 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544017 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544017 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544019 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544019 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544020 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544020 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544021 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544021 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544022 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544022 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544024 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544024 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544025 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544025 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544026 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544026 COLOUR EXPLAINED lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544027 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544027 HOW A RAINDROP FORMS A RAINBOW - VIA DISPERSION OF LIGHT lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544028 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544028 HOW RAIN DROPS REFRACT LIGHT TO FORM A RAINBOW lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544030 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544030 HOW A PRISM REFRACTS LIGHT INTO ROYGBIV - DISPERSION lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544031 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544031 PRISMS AND DISPERSION lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544032 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544032 MIXING COLOURS LAB lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544033 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544033 TEST PREP - LIGHT AND LENSES lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544034 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544034 MEMO lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544035 2022-05-09 11:49:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175544035 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175550240 Generally:
    • Convex lenses form real images, but can also form virtual depending on object position relative to focal point.
    • Concave lenses form virtual images.
    ]]>     2022-05-09 11:54:38 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175550240     LIGHT DISPERSION ANIMATION lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175558637 USING A PRISM TO DISPERSE WHITE LIGHT INTO ROYGBIV

    ]]>     2022-05-09 12:01:50 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175558637     LIGHT DISPERSION - ROYGBIV lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175562616
  • Violet light is slowed down most by glass and is refracted most; 
  • Red light slows down least and is refracted least. 
  • As a result, the colored light spreads out to form a spectrum of white light. 
  • This is called dispersion.
    • ]]>     2022-05-09 12:05:20 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2175562616     TOTAL ECLIPSE OF THE MOON = UBRA = BLOOD MOON lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2182855232 As the moon moves into the full shadow (umbra), you will begin to see the red color called blood moon, first on the side of the moon, which then gradually spreads over the entire moon.]]> 2022-05-13 13:12:48 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2182855232 NEXT TOTAL LUNAR ECLIPSE - MONDAY 16 MAY 2022! lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2182855528 2022-05-13 13:12:58 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/2182855528 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/3459093259 2025-05-20 10:06:38 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/3459093259 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/3928447872 2026-05-25 12:31:30 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/3928447872 lizellexs https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/3929880696 2026-05-26 11:25:17 UTC https://padlet.com/lizellexs/h5hslcbahs10rtql/wish/3929880696