The Human Eye and the Colourful World_Storyboard

Screen  Number		1.
Section		Prerequisites and Learning objectives
Screen Title		The Human Eye and the Colourful World
Events	Graphics/Animation Details		On Screen Text	VO
1.			Prerequisites: Basic properties of light, like rectilinear propagation of light. Reflection Refraction Image formation by Spherical mirrors Image formation by Spherical lenses Know about some important terms in image formation	Prerequisites: To start this chapter requires a firm understanding of the following: Basic properties of light, like rectilinear propagation of light. Reflection Refraction Image formation by Spherical mirrors Image formation by Spherical lenses Know about some important terms in image formation
2.			Learning objectives: Knowledge on The Human Eye Understand the concept  of Power of Accommodation: Gain the knowledge and skill on finding Defects of vision and their correction: Understand the concept  of Refraction of light through a prism Gain the knowledge on Dispersion of white light by a glass PRISM Recognize the part of light rays in Atmospheric refraction And Scattering of light	Learning objectives: After completing this chapter student will able to: Knowledge on  The Human Eye Understand the concept  of Power of Accommodation: Gain the knowledge and skill on finding Defects of vision and their correction Understand the concept of Refraction of light through a prism Gain the knowledge on Dispersion of white light by a glass prism Recognize the part of light rays in  Atmospheric refraction And Scattering of light
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Screen  Number		2.
Section		Introduction
Screen Title		The Human Eye and the Colourful World
Events	Graphics/Animation Details		On Screen Text	VO
3.	Show image formation by lenses.		Introduction: ·         What is refraction of light? How images are formed by lenses and what is the nature, position and relative size of those images?	Introduction: ·         What is refraction of light? How images are formed by lenses and what is the nature, position and relative size of those images?
4.	Show reflection and refraction by animation		‘Light - Reflection and Refraction’	We can give the answers to above questions based on previous knowledge which is studied in the chapter ‘Light- Reflection and Refraction’.
5.	Show the eye image/animation:			These ideas can help us to study of the human eye.
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Screen  Number		3.
Section		Explanation
Screen Title		11.1 THE HUMAN EYE
Events	Graphics/Animation Details		On Screen Text	VO
1.	Rotate the eye from front view to side view and stop cam.			The human eye: is the most valuable and sensitive sense organ and it is a natural optical instrument. The eye is nearly spherical in shape with a slight bulge in the front part, and it enables us to see the beautiful, colorful world around us.
2.	Indicate all the labels as per VO.		The important parts of the eye: Cornea: Iris: Pupil:	Let us discuss about the important parts of the eye and their functions: Cornea: The front part of the eye is covered by transparent spherical membrane called cornea.  Light enters the eye through cornea. Iris: Just behind the cornea is a dark coloured muscular diaphragm which has a small circular opening in the middle. Pupil: Pupil is the small circular opening of iris. The pupil appears black because no light is reflected from it. The dark center in the middle of the iris. The pupil determines how much light is let in to the eye.  It changes sizes to accommodate for the amount of light that is available.  The iris regulates the light by adjusting the size of the pupil.
3.				Let us see how iris regulates and controls the amount of light entering the eye: When the intensity of light is more or if it is a bright source of light then the iris makes the pupil to contract and as a result the amount of light entering the eye decreases. When the intensity of light is less or if the light is dim then the iris dilates the pupil so that more light can enter the eye.
4.			Eye Lens: Retina: Blind Spot:	Eye Lens: The eye lens is a convex lens made of a transparent jelly - like proteinaceous material. The eye lens is hard at the middle and gradually becomes soft towards the outer edges. The eye lens is held in position by ciliary muscles. The ciliary muscles help in changing the curvature and focal length of the eye lens. Retina: The inner back surface of the eye ball is called retina. It is a semi-transparent membrane which is light sensitive and is equivalent to the screen of a camera. The light sensitive receptors of the retina are called rods and cones. When light falls on these receptors they send electrical signals to the brain through the optic nerve. The space between the retina and eye lens is filled with another fluid called vitreous humour. Blind Spot: It is a spot at which the optic nerve enters the eye and is insensitive to light and hence the name.
5.			Accommodation of the eye  Power of Accommodation	Let us discuss about Accommodation of the eye and Power of Accommodation.
6.	Show the movement of (expansion and compression) ciliary muscles when falling light.		Accommodation of the eye:	Accommodation of the eye: The process by which the ciliary muscles change the focal length of an eye lens to focus distant or near objects clearly on the retina is called the accommodation of the eye.
7.	Muscles are expansion and the eye lens become thin. Muscles are compress and the eye lens become thick.			Power of Accommodation: The ability of the eye to focus objects lying at different distances is called the power of accommodation of the eye. How Does an Eye Focus Objects at Varying Distances? When the ciliary muscles are relaxed, the eye lens becomes thin. Thus, its focal length increases and we see the distant objects clearly. When the ciliary muscles are contract, then the curvature of the eye lens is increases and the eye lens becomes thick. Thus, its focal length decreases and we see the nearby objects. In brief it is the adjustment of the focal length of the eye lens which enables us to focus on objects situated at different distances.
8.	Show the following animation: A boy see near object, show wit camera animation		Least Distance of Distinct Vision (Near point):	Least Distance of Distinct Vision (Near point): Near point or least distance of distinct vision is the point nearest to the eye at which an object is visible distinctly. For a normal eye the least distance of distinct vision is about 25 centimetres. However, it varies with age of the person. For example, for infants it is only 5 to 8 cm.
9.	Show the far point of the eye.		The far point of the eye:	The far point of the eye: Far point of the eye is the maximum distance up to which the normal eye can see things clearly. It is infinity for a normal eye.
10.	Show the milky and cloudy eyes in old character . Indicate labels as per  the words(bold) in VO.		Cataract:	Cataract: The crystalline lens of people at old age becomes milky and cloudy. This condition is called cataract. This causes partial or complete loss of vision. It is possible to restore vision through a cataract surgery.
11.	Show the distance between the near and the far point.		Range of Vision:	Range of Vision: The distance between the near point and the far point is called the range of vision.
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Screen  Number		4.
Section		Explanation
Screen Title		11.2 DEFECTS OF VISION AND THEIR CORRECTION
Events	Graphics/Animation Details		On Screen Text	VO
1.			DEFECTS OF VISION AND THEIR CORRECTION:	DEFECTS OF VISION AND THEIR CORRECTION: The eye may gradually lose its power of accommodation. In such conditions, the person cannot see the objects distinctly and comfortably. The vision becomes blurred due to the refractive defects of the eye.
2.	Show the types of defects of eye in  tree diagram with lables.		Myopia or near-sightedness, Hypermetropia or farsightedness, Presbyopia.	There are mainly three common refractive defects of vision. These are (i)                 Myopia or near-sightedness, (ii)               Hypermetropia or farsightedness, and (iii) Presbyopia. These defects can be corrected by the use of suitable spherical lenses. We discuss below these defects and their correction.
3.	Show the following animation:		Myopia: The light from a distant object arriving at the eye lens may get converged at a point in front of the retina in the vitreous body. This type of defect is called near sightedness or myopia. The correction for myopia:	Myopia: The light from a distant object arriving at the eye lens may get converged at a point in front of the retina in the vitreous body. This type of defect is called near sightedness or myopia. Let us observe these cases, and then you can understand the concept ‘myopia’. In the case of normal eye, the light rays from the object fall on the eye and converge on the retina. In the case of myopic eye, the light rays from the object fall on the eye and focuses the light at a point in front of the retina in the vitreous body The correction for myopia: To compensate this, we interpose a concave lens between the eye and the object, with the diverging effect desired to get the image focused on the retina.
4.	Show the formation of image in hypermetropic eye, normal eye and its correction with ray diagrams.		Hypermetropia: If the eye-lens focuses the incoming light at a point behind the retina, this defect is called far sightedness or hypermetropia.  The correction for hypermetropic eye:	Hypermetropia: If the eye-lens focuses the incoming light at a point behind the retina, this defect is called far sightedness or hypermetropia. Let us observe these cases, and then you can understand the concept ‘hypermetropia’. In the case of normal eye, the light rays from the object fall on the eye and converge on the retina. In the case of hypermetropic eye, the light rays from the object fall on the eye and focuses the incoming light at a point behind the retina. The correction for hypermetropic eye: A convergent lens is needed to compensate for the defect in vision.
5.	Show the formation of image in pesbyopic eye, normal eye and its correction with ray diagrams.		(c) Presbyopia:	(c) Presbyopia: What is presbyopia? Presbyopia is a common type of vision disorder that occurs as you age. It is often referred to as the aging eye condition. Presbyopia results in the inability to focus up close, a problem associated with refraction in the eye. How does presbyopia occur? Presbyopia happens naturally in people as they age. The eye is not able to focus light directly on to the retina due to the hardening of the natural lens. Aging also affects muscle fibers around the lens making it harder for the eye to focus on up close objects. The ineffective lens causes light to focus behind the retina, causing poor vision for objects that are up close.
6.	Show the boy (long shot) and his eye lens (close up shot).			When you are younger, the lens of the eye is soft and flexible, allowing the tiny muscles inside the eye to easily reshape the lens to focus on close and distant objects.
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Screen  Number		5.
Section		Explanation
Screen Title		11.3 REFRACTION OF LIGHT THROUGH A PRISM
Events	Graphics/Animation Details		On Screen Text	VO
1.	Show the following animation: Light passing through a glass slab. Show all sides of the prism on the table with camera movement.			In the previous chapter You have learnt how light gets refracted through a rectangular glass slab.  For parallel refracting surfaces, as in a glass slab, the emergent ray is parallel to the incident ray. However, it is slightly displaced laterally. How would light get refracted through a transparent prism? Consider a triangular glass prism. It has two triangular bases and three rectangular lateral surfaces. These surfaces are inclined to each other. The angle between its two lateral faces is called the angle of the prism. Let us now do an activity to study the refraction of light through a triangular glass prism.
2.	Show the following animation: Take the prism and place on the table as shown that it rests on its triangular base.  Trace the outline of the prism using a pencil.			Fix a sheet of white paper on a drawing board using drawing pins. Place a glass prism on it in such a way that it rests on its triangular base. Trace the outline of the prism using a pencil. Draw a straight line PE inclined to one of the refracting surfaces, say AB, of the prism.  Fix two pins, say at points P and Q, on the line PE as shown in Figure.  Look for the images of the pins, fixed at P and Q, through the other face AC. Fix two more pins, at points R and S, such that the pins at R and S and the images of the pins at P and Q lie on the same straight line.  Remove the pins and the glass prism.  The line PE meets the boundary of the prism at point E. Similarly, join and produce the points R and S. Let these lines meet the boundary of the prism at E and F, respectively. Join E and F.  Draw perpendiculars to the refracting surfaces AB and AC of the prism at points E and F, respectively.  Mark the angle of incidence (∠i), the angle of refraction (∠r) and the angle of emergence (∠e) as shown in Figure.
3.				Here PE is the incident ray, EF is the refracted ray and FS is the emergent ray. You may note that a ray of light is entering from air to glass at the first surface AB. The light ray on refraction has bent towards the normal. At the second surface AC, the light ray has entered from glass to air. Hence it has bent away from normal.  Compare the angle of incidence and the angle of refraction at each refracting surface of the prism.  Is this similar to the kind of bending that occurs in a glass slab? The peculiar shape of the prism makes the emergent ray bend at an angle to the direction of the incident ray. This angle is called the angle of deviation. In this case ∠D is the angle of deviation. Mark the angle of deviation in the above activity and measure it.
4.
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Screen  Number		6.
Section		Explanation
Screen Title		11.4 DISPERSION OF WHITE LIGHT BY A GLASS PRISM
Events	Graphics/Animation Details		On Screen Text	VO
1.				You must have seen and appreciated the spectacular colours in a rainbow. How could the white light of the Sun give us various colours of the rainbow? Before we take up this question, we shall first go back to the refraction of light through a prism. The inclined refracting surfaces of a glass prism show exciting phenomenon. Let us find it out through an activity.
2.	Show the following animation: White light passing through a glass prism and divided into seven colours.			If a prism is placed in a room and a narrow beam of white light is allowed to fall on one of its refracting faces, What do you observe? It is found that light coming out from the other face of the prism is split in to seven colors. What are the seven colours that you see on the screen? The various colours seen are Violet, Indigo, Blue, Green, Yellow, Orange and Red. This phenomenon (the splitting of light into its component colours) is called dispersion of light. The band of the coloured components of a light beam is called its spectrum. Why does this happen?
3.				The acronym VIBGYOR will help us to remember the sequence of colours. We have seen that white light is dispersed into its seven-colour components by a prism.
4.				Why do we get these colours? Different colours of light bend through different angles with respect to the incident ray, as they pass through a prism. The red light bends the least while the violet the most. Thus the rays of each colour emerge along different paths and thus become distinct. It is the band of distinct colours that we see in a spectrum.
5.	Place two glass slabs in similar position and white light is scattered through first prim it fall on second prism.			Isaac Newton was the first to use a glass prism to obtain the spectrum of sunlight. He tried to split the colours of the spectrum of white light further by using another similar prism. However, he could not get any more colours. He then placed a second identical prism in an inverted position with respect to the first prism.
6.	Place two glass slabs in similar position and white light is scattered through first prism it falls on second prism emerged as white light.			This allowed all the colours of the spectrum to pass through the second prism. He found a beam of white light emerging from the other side of the second prism. This observation gave Newton the idea that the sunlight is made up of seven colours. Any light that gives a spectrum similar to that of sunlight is often referred to as white light.
7.	White light passing through water bubble it is divided into colours as shown in figure.			A rainbow is a natural spectrum appearing in the sky after a rain shower. It is caused by dispersion of sunlight by tiny water droplets, present in the atmosphere.  A rainbow is always formed in a direction opposite to that of the Sun. The water droplets act like small prisms. They refract and disperse the incident sunlight, then reflect it internally, and finally refract it again when it comes out of the raindrop.
8.				Due to the dispersion of light and internal reflection, different colours reach the observer’s eye. You can also see a rainbow on a sunny day when you look at the sky through a waterfall or through a water fountain, with the Sun behind you.
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Screen  Number		7.
Section		Explanation
Screen Title		11.5 ATMOSPHERIC REFRACTION
Events	Graphics/Animation Details		On Screen Text	VO
1.	Show the wavering image Show the twinkling of stars			We have observed some natural phenomena in our daily life, such as, The apparent random wavering or flickering of objects seen through a turbulent stream of hot air rising above a fire or a radiator. The twinkling of stars is a similar phenomenon. This wavering is thus an effect of atmospheric refraction (refraction of light by the earth’s atmosphere) in our local environment.  Let us discuss about them.
2.	Show the twinkling of a stars is due to atmospheric refraction of starlight		Twinkling of stars:	Twinkling of stars: The twinkling of a star is due to atmospheric refraction of starlight. The scientific name for the twinkling of stars is stellar scintillation (or astronomical scintillation). Stars twinkle when we see them from the Earth's surface because we are viewing them through thick layers of turbulent (moving) air in the Earth's atmosphere.
3.	Show the above animation and give the lables			Stars (except for the Sun) appear as tiny dots in the sky; as their light travels through the many layers of the Earth's atmosphere, the light of the star is bent (refracted) many times and in random directions (light is bent when it hits a change in density - like a pocket of cold air or hot air). This random refraction results in the star winking out (it looks as though the star moves a bit, and our eye interprets this as twinkling).
4.	Show the following animation: The light ray travels through the earth layers with reflection and reach the observer as shown in figure.			Stars closer to the horizon appear to twinkle more than stars that are overhead - this is because the light of stars near the horizon has to travel through more air than the light of stars overhead and so is subject to more refraction. Also, planets do not usually twinkle, because they are so close to us; they appear big enough that the twinkling is not noticeable (except when the air is extremely turbulent). Stars would not appear to twinkle if we viewed them from outer space (or from a planet/moon that didn't have an atmosphere)
5.	The light ray travels through the earth layers with reflection and reach the observer as shown in figure.		Apparent position of sun:	Apparent position of sun: Because of atmospheric refraction, we do not see the sun (or the stars) in its true position except when it is directly overhead. As a ray of light from the sun enters earth’s atmospheric at B, it continuously bends towards radius of the earth. The ray of light will reach the observer at O as if it had come in the direction AO instead of in its true direction BO. Consequently, we do not see the true position of the sun. It is due to atmospheric refraction that the sun is visible before actual sunrise and after actual sunset.
6.	Sunrise animation			Do you know this fact? The sun appears to rise 2 minutes before the actual rise and it continues to be seen 2 minutes after it has actually set. Therefore, the day becomes longer by 4 minutes due to atmospheric refraction.
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Screen  Number		8.
Section		Explanation
Screen Title		11.6 SCATTERING OF LIGHT
Events	Graphics/Animation Details		On Screen Text	VO
1.	Show the sunrise and sunset images.		The blue colour of the sky, Colour of water in deep sea, The reddening of the sun at sunrise and the sunset are.	We have across some wonderful phenomena in our daily life, such as The blue colour of the sky, Colour of water in deep sea, The reddening of the sun at sunrise and the sunset are. What is the reason behind these natural phenomena? For this, first we shall discuss about ‘Scattering of light’.
2.	Show the animation, how the light is scattered when it strikes the atmospheric particles.		Scattering of light:	Scattering of light: When a beam of light falls on an atom, it causes the electron in the atom to vibrate. The vibrating electrons, in turn, re-emit light in all directions. This process is called scattering.
3.	Show above animation.		The intensity of scattered light varies inversely as the fourth power of the wave length of height (1/h4).	Earth’s atmosphere contains air molecules and other tiny particles. When light from the sun passes through the atmosphere, it gets scattered by the large number of particles in the atmosphere. According to Rayleigh law, the intensity of scattered light varies inversely as the fourth power of the wave length of height (1/h4).
4.	Show the John Tyndall s photo and give some description.		Tyndall Effect:	Tyndall Effect: John Tyndall was the first one to explain about the color of the sky in the year 1859. He stated that the color blue shatters (scattered) more than that of red due to the shorter wavelength in a case where the light has to pass through a clear fluid that contains suspended small particles.
5.	The sun light passes through dust particles. The sun light passes through water particles.			Our planet earth consists of various mixtures of particles like smoke, molecules of air, dust particles and water droplets.  These diffused particles reflect the light before it reaches the earth. The scattering of the light by the colloidal particles is known as the Tyndall effect.
6.			The size of the particles determines the color of the scattered light.	The size of the particles determines the color of the scattered light. This statement can be proved with the help of a simple experiment.   Allow a beam of light to pass through a tank of water with a slight mixture of soap or milk in it.  If you watch the beam from a side you can notice that the beam scatters blue light but when you thoroughly observe the beam from the end then you will find that the beam is reddened after it has passed through the tank.
7.	Sun light ray travels towards earth atmosphere  and		Why is the colour of the clear Sky Blue?	Why is the colour of the clear Sky Blue? Since the wave length of blue colour is smaller than the wavelength of red colour ( (lambda b less than lambda r).scattering of blue light by particles in earth’s atmosphere is very large. For this reason we see a blue sky. Although violet light is scattered more than blue light, our eyes are not very sensitive to violet light.
8.			Colour of the Sun at Sunrise and Sunset:	Colour of the Sun at Sunrise and Sunset: At the time of sunset or sunrise, the sun is near the horizon as shown in diagram. The rays from the sun must travel more kilometers through the atmosphere than at noon. Therefore, more blue is scattered from the sunlight. The removal of blue leaves the transmitted light more reddish in appearance. Therefore, sun looks reddish at the sunset or sunrise.
9.				The Raman effect was theoretically predicted in 1923 The first experimental observation was made by C V Raman in 1928. That is,  If light of a definite frequency is passed through any substance in gaseous, liquid or solid state, the light scattered at right angles contains radiations not only of the original frequency (Rayleigh Scattering)  but also of some other frequencies which are generally lower but occasionally higher than the frequency of the incident light. The phenomenon of scattering of light by a substance when the frequencies of radiations scattered at right angles are different (generally lower and only occasionally higher) from the frequency of the incident light, is known as Raman Scattering or Raman effect. The lines of lower frequencies as known as Stokes lines while those of higher frequencies are called anti-stokes lines. If f  is the frequency of the incident light &  f’  that of a particular line in the scattered spectrum, then the difference   f-f’   is known as the Raman Frequency. This frequency is independent of the frequency of the incident light. It is constant and is characteristic of the substance exposed to the incident light. A striking feature of Raman Scattering is that Raman Frequencies are identical, within the limits of experimental error, with those obtained from rotation-vibration (infrared) spectra of the substance.
10.				Uses:  Investigation of biological systems such as the polypeptides and the proteins in aqueous solution.  Determination of structures of molecules. RAMAN was awarded the 1930 Physics Nobel Prize for this.
11.
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