Script for
Light Magic

This slideshow is designed for lower primary.  Main focus is to get students to look at teeth to help determine their position on the food web.

Slide 1.

·       Discuss with the students the subject of light.  What is light?  Where does it come from?  Accept all answers even if they are way out there! This is the time when you are finding out from them what they know about science and their comfort zone with you!  

Slide 2.

·       How can we see light?

·        Use eyeball model, go over parts of the eye, how light moves through.  Our eyes have adapted to sense light from the sun. Our eyes see the world upside down and our brain turns the image right side up.

Slide 3.

·       Ask the kids to come up with a hypothesis; why do aliens have big eyes?

·       If aliens are from a planet far from sunlight, they would need big eyes to capture light.  Our face uses eyes to take advantage of light.

Slide 4.

·       Light is actually made of something called photons or electromagnetic radiation. 

·       Prove it to students by making light move.

·       Notice that the “tree” flips when it goes through the lens. 

·       The lens is similar to our eye lens. Light is refracted.

Slide 5.

·       Compare lenses and mirrors and their shapes.

·       If light goes through it is refracted and scatters the light.

·       If light encounters a mirror it will be reflected.

Slide 6.

·       Light is part of the electromagnetic wave spectrum.

·       The speed of light is 300,000 km/sec; can a rocket fly faster? Can a meteor fall faster? (Speed limit of matter and energy).

·        Light can be reflected, refracted, or diffracted. Light in motion can act like a wave and a particle.

Slide 7.

·       There are 2 types of waves, physical and electromagnetic.  Sound is an example of physical; and light is a sample of electromagnetic. 

·       Use the picture to see other examples from radio to x-rays. 

·       Electromagnetic waves have the same speed. 

Slide 8.

·       Wavelengths of visible light are measured in nanometers. Red light has a longer wavelength than blue light, so blue has to wiggle extra to keep up with red.

·       When light breaks up due to refraction you get the rainbow.  It is always in the same sequence, knows as ROY G. BIV.

Slide 9.

·       All light travels at the same speed. Albert Michelson experimented with light to determine its speed.

·        He refined earlier experiment conducted by Leon Foucault.           

 Slide 10.

·       Light interacts with substances and objects. It is reflected, refracted, or diffracted.

·       Refraction goes through a substance and because it is different type it will deflect a little.

·       Reflection is when light bounces from the mirror surface.

·       Diffraction is when light goes through a small slit and shows a pattern and the light branches out.

·       Next activity is to see if you can determine what is refraction, reflection or diffraction.

Slide 11.

·       Reflection is when a wave bounces off a surface back toward the source. Have the children hypothesize what happens to the image when it is reflected by flat, concave, and convex mirrors stepwise respectively. Reinforce concave and convex.

Slide 12.

·       Refraction of light happens when waves are deflected as they pass through a substance. (A change in direction of the wave due to a change in the medium it passes through i.e. air, water, glass). Light travels through water and air at different speeds. Different      wavelengths of light can be separated out from white light (dispersion) using a prism.         

Slide 13.

·       Diffraction occurs when a wave travels through a small opening and flares out revealing a diffraction pattern.

Slide 14.

·       Light can move as a wave and as a particle.  A light particle is called a photon.

·       Light waves travel along a linear path but can change direction as they enter a different medium (i.e. from air to glass/water). [F.Y.I. Wave propagates through electric and magnetic fields].

Slide 15.

·       What produces light?  Many things- Incandescence, excitation, fluorescence, and phosphorescence.


·       Light emitted from an incandescent lamp is white .  All the frequencies are emitted.  This had to do with the atom acting in a solid.   Most incandescent bulbs are made from tungsten, a solid. 

·       Light is emitted through radiation or heat.  Stars give off light because of radiation.  The temperature of incandescent bodies depends on the color of the radiation they emit.

Slide 17.  EXCITATION.

·       When an electron is excited to a higher energy level, the atom is said to be excited. The electron's higher level is only temporary, as it goes from high energy level back to normal level. 

·       The atoms lose its temporarily acquired energy when the electron returns to a lower level. 

·       The energy released is in the form of photons which our eyes see as light.  Light emitted from a neon sign is an example of excited neon gas.  Millions of electrons vibrate back and forth inside the glass tub and smash into atoms, this constant bombardment and returning to the normal level emits the characteristic red light of neon. 

·       The cycle of excitement to de-excitation.  Another example is the new type of mercury vapor street lights.  The light is emitted by the excitation of the vapors.  Not only is the light brighter, but it is less expensive and lasts longer than incandescent lamps. 


·       When you have some materials that are excited by ultraviolet light upon a de-excited photon, you get fluorescence.  

·       In a fluorescent lamp, the tube is filled with very low pressure mercury vapor which is excited by the impact of the high-speed electrons. 

·       Upon de-excitation, energy is released as a photon of light. Fluorescent paints can cause it to glow red, yellow or some other color when bombarded with photons in sunlight.  If you put these same paints under ultraviolet lamps, the color will be more intense.



·       Some materials stay in an excited state longer than others. 

·       As a result there is time between the process of excitation and de-excitation.  This is called phosphorescence.   

·     Atoms are excited by visible light.  The afterglows may last from fractions of a second to hours, even days to years.

Slide 20.

·       Products from light “Photonics” is the exploration of light in devices and systems.


    Slide 21.

·       TVs and Computer screens use pulsating pixels of red, blue, and green in patterns that allow our eye to see them as an image of many colors.

·       Red, blue, and green light is added together in various ways to reproduce a large variety of colors. 

·       High definition TV, has an added yellow. 

Slide 22. (L.ight A.mplification S.imulated E.mission of R.adiation)

·       Laser is coherent light, meaning all the wavelengths march together. [F.Y.I. Basis can be found in (Einstein coefficients) for the absorption, spontaneous emission, and stimulated emission of electromagnetic radiation.

·       In the laser beam all new photons enter the electromagnetic field with identical phase, frequency, polarization, and direction]

          Students must first understand two terms:  coherent and incoherent light.  Light emitted by normal means such as a flashlight or a bulb, is incoherent; meaning that the photons of the many wave frequencies of light are oscillating in different directions.  It is not a stream of light.  Coherent light is a beam of photons (almost like particles of light waves) that have the same frequency and are all at the same frequency.  Only a beam of laser light will not spread and diffuse.  In lasers, waves are identical and in phase, which produces a beam of coherent light.  There are many types of lasers that use gases such as helium, neon, argon, and carbon dioxide.  Lasers also use semiconductors (Galiodium and Arsenic), solid-state material (ruby, glass), and even chemicals (hydrofluoric acid) in their operation.

Slide 23.

·       Cameras use incoherent light to make 2D images (film or digital).

·       3D images are made with coherent light (lasers). This is a hologram.

Slide 24.

·       Light can carry information. Fiber Optics uses special fibers and total internal reflection to keep light traveling along a directed path.

Slide 25.   Photonics

·       There are still many products that can be developed with the understanding of light