Light Reflection and Refraction

  • View
    127

  • Download
    0

Embed Size (px)

DESCRIPTION

Light Reflection and Refraction. Learning Outcomes. Lessons. Learning Outcomes. Lessons. Learning Outcomes. Lessons. Light is a Form of Energy. the source of energy for plants Indirect source of energy for animals. Light Energy. Light kinetic energy Crookes Radiometer. - PowerPoint PPT Presentation

Transcript

  • LightReflection and Refraction

  • Lessons

  • Learning OutcomesLessons

    OP33understand that light is a form of energy and that it can be converted to other formsOP34show that light travels in straight lines and explain how shadows are formedOP35understand that luminous objects are a source of light while non-luminous objects are seen as a result of light reflected from them

  • Learning OutcomesLessons

    OP36Recall that white light is made up of different colours which can be separated by dispersionOP37Produce a spectrum of white light using appropriate apparatus, and list the colours of the spectrum.

  • Learning OutcomesLessons

    OP38investigate the reflection of light by plane mirrors, and illustrate this using ray diagrams; demonstrate and explain the operation of a simple periscope OP39show the refraction of light as it passes from: air to glass, air to water, glass to air, water to air; show refraction of light through a lens; demonstrate the operation of a magnifying glass

  • Light is a Form of Energythe source of energy for plantsIndirect source of energy for animalsLight Energy

  • Conversion of Light EnergyLight kinetic energy

    Crookes RadiometerLight Electrical Energy

  • Luminous/Non-Luminous BodiesAn object is seen when light from it reaches eyes

    Luminous objects give out light

    Non-luminous objects dont give out light

    How can we see non-luminous objects?

    Sources of light luminous objectsSun, stars, candle, lamp, fire and other chemical reactions

  • Seeing Non-Luminous Objectsluminous objectNon-luminous object

  • Transmission of LightLight travels in straight linesCan you give examples?

  • To Show That Light Travels in Straight LinesMandatory Practicallight bulbcardboardthread/string

  • To Show the Formation of ShadowsMandatory PracticalTorchWhite Sheet/CardboardObjectThis also shows that light travels in straight lines.

  • Light Speed300 million metres per second (3x108 m/s)

    Sun Earth (150million miles)takes ~8 minutes

    Light year distance light travels in 1 yearHow many seconds in a year? Answer: 9,460,000,000,000km

  • ReflectionPractically all surfaces reflect lightShiny smooth surfaces have regular reflection

    Matt (dull) surfaces have scattered reflection

  • Uses of ReflectionWhat are some uses of reflection?Mirror, periscope (used in submarines)mirror at 45o anglePeriscope

  • To show reflection of light by a plane mirror and to demonstrate the operation of a periscopeMandatory Practicallight boxbulb inside boxsheetmirrorlight boxFrom the topmirrorpencil mark

  • Refraction of LightWhy do objects appear contorted under water? Why does a swimming pool look shallower than it really is?

    Light travels in straight lines through air, glass, water etc.BUTWhen it passes from one to the other it changes direction.

    Refraction is the bending of light from one medium to another

  • Refraction Demonstrationlight boxsheetglass blockrefraction fromair to glass occurs herePlan view of experiment to demonstrate refraction

  • LensesSimple optical devicesCurved surfaces use refraction to focusConvex/converging lens (fat in the middle)

    Concave/diverging lens (thin in the middle)Example: magnifying glassExample: lenses of short sighted people

  • Spectrum of White Light

  • Spectrum of LightWhere do the colours of the rainbow come from?Are they always the same colours?YES!

    The name given to the splitting up of white light into its separate colours is dispersionColour SpectrumRed, Orange, Yellow, Green, Blue, Indigo and Violet

  • Producing a Colour Spectrumlight boxbulb inside boxpaper or cardprismscreenColour SpectrumRed, Orange, Yellow, Green, Blue, Indigo, Violet

  • Homework SuggestionsWhy is the sky blue?Why are sunsets orange?Why is sunburn more likely to occur if you are up a high mountain or at the beach?How do photosensitive sunglasses work?Why are soap bubbles coloured in white light?Why are compact discs coloured?Why are sunglasses of particular benefit to fishermen?How would a rainbow appear to passengers in an aeroplane when there is rain in the air above and below them?Why do materials purchased in a shop appear a different colour in daylight?How does the eye see colour?What causes after images and what colour are they?If black is a good absorber of heat, why do Bedouins wear black robes in the hot desert? Why is the filament of an electric light bulb coiled?Why is a firefly a more efficient light producer than a filament lamp?

  • Light Cloze Test ALight is a form of ______. In a piece of apparatus called a ______, light energy is converted to ______ energy, and in the process of photosynthesis it is converted to ______ energy. Animals get energy ______ from this process. Light travels in ______ lines, but it can be made to change direction in two ways by ______ and ______. When light strikes a mirror it is ______ and when it enters a glass block it is ______.

  • Light Cloze Test BLight, on being passed through a ______, is split up into its component colours. This process is known as ______ and the band of colours which is formed is called a ______. The colours are red, ______, ______, ______, ______, ______, ______. When all of these colours are recombined, ______ light is produced. This property of light was discovered by a scientist named ______. An example of real-life dispersion is a ______.

  • Light Cloze Test CAn experiment to show that light travels in ______ lines includes a light box, ______ sheets with a ______ in the centre, a piece of ______ used to align the sheets and a ______ as a source of light. If the sheets are not-aligned the viewer sees ______ and if they are aligned the viewer sees ______. To see the effect of shadows you require:______, ______ and a ______When the torch is turned on in a darkened environment the dark______ of the object appears on the ______. A light box, sheet, screen and a ______ ______ are required to show refraction from ______ to glass. To indicate ______, a triangular glass block known as a ______ is required which disperses the light and produces a ______ ______.

  • Light Cloze Test DA ______ glass is an example of a convex or ______ lens. This causes _____ rays to ______ at a point. The opposite type of lens is ______ in the middle and is know as a ______ lens. This causes light rays to ______ and is used in the glasses of ______ sighted people. If confronted by a tall wall, a ______ would enable you to see over it. They are more commonly found in ______ to see ______ the water surface. This works by placing ______ mirrors at an angle of ______.

  • ResourcesImageshttp://acept.la.asu.edu/PiN/mod/light/reflection/pattLight1Obj1.htmlhttp://science-education.pppl.gov/SummerInst/auroraborealis.jpg InformationDiagram & Info on Crooks Radiometerhttp://www.teachersparadise.com/ency/en/wikipedia/c/cr/crookes_radiometer.html Did you know questions for lightwww.juniorscience.ie/jsss/Main/3B3R.htmSyllabus informationwww.education.ie Info on light, reflection & refractionhttp://acept.la.asu.edu/PiN/mod/light/reflection/pattLight1.html Science Today, Physics Textbook SoundsFarm noiseshttp://www.grsites.com/sounds/farm001.shtml

    Topics: LightSubtopics: sources and transmission of light, speed of light, shadows; colour and the visible spectrum; dispersion and white light

    Topics: Reflection of Light; Refraction of LightSubtopics: reflection of light at plane surfaces; image in a plane mirror; refraction; refraction by lenses; application of reflection and refractionThis is a hidden slide and will not appear in any slide show. It does however link to the different lessons as I have split them up.Topics: LightSubtopics: Sources and transmission of light, speed of light, shadowsLesson Time: 40 minutes

    These learning outcomes are what the student will be able to accomplish after the lesson.The underlined learning outcomes indicate those for higher level students only.Learning outcomes coloured blue indicate practical work.PRESENTATION NOTES:Click on the learning outcome to view the presentation for that outcomeThis slide is hidden and will not appear in a screen presentation. It will appear in the notes only if you choose to print hidden slidesClick on the button Lesson Menu to go the lesson choice slide

    Lesson Time: 40 minutesTopics: LightSubtopics: colour and the visible spectrum; dispersion and white light

    These learning outcomes are what the student will be able to accomplish after the lesson.The underlined learning outcomes indicate those for higher level students only.Learning outcomes coloured blue indicate practical work.PRESENTATION NOTES:Click on the learning outcome to view the presentation for that outcomeThis slide is hidden and will not appear in a screen presentation. It will appear in the notes only if you choose to print hidden slidesClick on the button Lesson Menu to go the lesson choice slide

    Lesson Time: 40 minutesThese learning outcomes are what the student will be able to accomplish after the lesson.The underlined learning outcomes indicate those for higher level students only.Learning outcomes coloured blue indicate practical work.PRESENTATION NOTES:Click on the learning outcome to view the presentation for that outcomeThis slide is hidden and will not appear in a screen presentation. It will appear in the notes only if you choose to print hidden slidesClick on the button Lesson Menu to go the lesson choice slide

    Slide Aim:To show light as a source of energyLight can be converted from one form of energy to another

    Probing Questions?With respect to flowers, what effect does the sun have?