LightI can identify a wide range of sources of light, including the sun, various forms of electric lights, flames, etc.• Light is a form of energy just like kinetic energy, potential

energy, gravitational energy, sound, or heat. • There are two types of light energy; man-made and natural.

Light from the sun is called solar energy. • Light is white and it travels in waves. Light travels in a

straight line from the source.• It is not visible to the human eye; you can’t see it.• Light travels from a light sources (i.e. solar, natural, and

man-made). The temperature of these light sources is HOT.• Some objects emit their own light and others require an

external source of light to be seen.• Something that can glow and emits its own light is

luminescent. The temperature of a luminescent things (that are alive or dead) is not high/cooler.

• You cannot look at bright light as it can damage her eyes.• When light bounces off a shiny/smooth object it creates a

reflection.• When light goes through a prism-like object (clear,

glass/plastic/many layers) the light bends and creates different colours of the rainbow (dispersion of light).

Objects that Emit Light (Man-made)

Objects the Emit Light (Natural)

Observations • The sun/flashlight or any source of light emits light and hits

an objects which will then reflect light off that object. • The characteristic/qualities (i.e. colour, texture, brightness,

etc.) all play a role in the intensity of the reflecting light and the intensity of the reflection.

• Objects can also reflect light if they are light in colour, shiny or clear and they don’t reflect as much light as they get darker.

• The type of material also affects the intensity of the reflection of light (i.e. a glass or mirror is clear and it will reflect light brightly or clearly versus a plastic material or a non-shiny metal which will not reflect light as clearly or brightly.

Sources of Light Natural Light Man-made LightSun Traffic LightsFireflies Car lights/headlightsNatural fire (i.e. forest fire) Fire (i.e. match sticks, lighters,

etc.)

Sunlight Safety • Viewing the sun without proper equipment can result in

permanent eye damage. Sunglasses, binoculars, and telescopes do not provide adequate protection from direct observation of the sun.

• Additionally, never look directly at a source of light, whether it’s man-made and natural.

• Safe to view the sun: Welder’s glasses available in hardware stores.

What does it mean?• When an object emits light it means that it can produce a

discharge of light whether it’s man-made or natural (i.e. flashlight – manmade, lava – natural).

• When an object reflects light, it bounces off an object. If the surface is smooth and shiny (like glass, water or a polished metal), then the light is bright and the reflection is a stronger. In comparison to light reflecting off dark objects. In

other words, when an object does not emit its own light, it must reflect.

Reflection of Light

Reflection• To bounce off of a surface. For example, light

that bounces off a mirror.• When light bounces off an object and creates

a reflection. • The object has to be good reflector to create

a good reflection. A good reflector appears to be smooth and/or shiny because it reflects light evenly and in one main direction. For example, mirrors, calm lake, and polished metals.

Refraction• The bending of a light ray as it passes through one object to

another.• When light rays bend as they pass from one object to

another.

• For example, when light passes through a prism (clear glass/surface) then the light rays bend and produce light.

• Light travels through a light source and passes through a glass bowl full of water. This bowl can act as a prism because it has many layers of something.

• Because of the light refracts in water, you can sometimes not tell the exact position of an object underwater. So, if you are standing at a dock and looking at fish in the lake, the fish underwater don’t always appear to be where actually is.

Good Reflectors (something shiny)

Bad Reflectors (something rough)

Steel water bottle

Blanket or any cloth

Metal legs/support of a chair

Wall (mostly dark colours)

Metal part of a scissors

Gravely path

Icy/frozen/calm body of water

Pencil/backpack

Mirror Boulder/rock

CD Old/dull Chalkboard

Coins Old/dull wooden

bench

Sequins Silicone plant pots

Rainbow• Nature’s display of the spectrum of colours produced by the

dispersion (spreading) of colours as light passes through the sky during a rainstorm. Droplets producing specific colours lie in arches of a circle across the sky which is why the rainbow takes the shape of an arc.

• Red• Orange• Yellow• Green• Blue• Violet

Colour Combinations• Different colours of light can be mixed to make a new colour.• The three primary colours are red, blue, and yellow. Primary

colours are originals and they cannot be made; they are made as is.

• The secondary colours are made when primary colours are mixed together. The secondary colours are orange, green and violet.

• Red with Yellow = Orange• Red with Blue = Violet• Blue with Red = Violet

• Blue with Yellow = Green• Yellow with Red = Orange• Yellow with blue = Green

Luminescent• Luminescent objects glow and are able to produce their own

light at low temperatures. • Luminescent materials emit their own light through a

chemical or physiological reaction.• The light is produced by two types of processes that produce

light:1. Fireflies and Lantern Fish (Physiological)2. Luminous paint; glow in the dark effect – which contains

zinc sulfide activated by copper (Chemical)The Moon and the Sun• Does the moon produce light?

• The moon does NOT produce light. The moon is a reflector and reflects sunlight. The moon’s surface is all rock.

• Does sun produce light?• The sun is the biggest natural producer of light in our

galaxy.• Why does the moon shine? How is it that we see the moon?

• It reflects sunlight and it makes the moon shine.• How is it that we see anything that does not produce light?

• Basically, everything that doesn’t produce light is a reflector of light or we can only see it because it reflects light.

Transparent Translucent Opaque

• See through or clear

• All light goes through

Examples:-Plastic Wrap-Glass Window-Clear tape-Clear/see-through glass doors or windows-Clear plastic Ziploc bag

• Some light goes through

• Kind of see-through

• In the middle

• Can create a shadow when light shines on it.

Examples: -Wax Paper-Lampshade-Light coloured/material cloth-Plastic part of Signs-Patterned covers on ceiling lights and wall lights-Thick plastic/clear binders-Layers of onion

• Not see-through

• No light goes through

• Can create a shadow when light shines on it.

Examples:-Cardstock or thick paper-Wall-Lockers (metal)-Thick carpet-Stairs-Hook-Floor -Wood

What is a shadow?• A shadow is a dark area or shape produced by a body

coming in between the rays of light and a surface. Other words to describe the word shadow are silhouette, outline, shape, profile, contour, etc.

• Shadows fall in the OPPOSITE direction of the light source shining on an object.

• Shadows change their direction and shape:1. When the sun rises from the east, the shadow is long

and fall on the opposite side of the object.2. When the sun is in the sky during midday (12:00p.m.),

the shadow was under or all around the object and it was shorter.

3. When the sun is in the sky during the evening and close to sunset, the shadow is on the opposite side and it longer again.

MORE ABOUT SHADOWS• Does the size of a shadow change throughout the course of a

day? Yes it change to a different size and position.• Explain how and why have the shadows changed? Shadows

change as the sun moves across the sky in the course of the day.

• What is the path of the sun? The sun rises from the east and sets in the west.

• Where will your shadows fall in the evening? It will be longer and almost fading into darkness.

Shadows & the Sun

Morning Sun Afternoon Sun Evening Sun

-Shadows are longer in the morning-Sun rises from the East-Time: Early Morning

-Sun is the highest in the sky-Shadows fall directly down-Shadows get shorter as the sun is higher in the sky.-Time: Midday

-Shadows are long-Sun sets in the West-Time: Late Afternoon-The shadows are longer again as the sun sets lower in the sky.

Convex Lens• Convex lens bends outwards or is curved out. • A convex lens refracts (bends) light.• When beams of light pass through a convex lens, they come

closer together (converge/meet) to a common point. This point is called a focus. When you place an object between the focus and the lens, the object will appear magnified (bigger).

• When you place the object away from the focus point, you will see an upside down image.

Concave Lens• Concave lenses cause light to spread out (diverge).• Things appear smaller through a concave lens.• Nearsighted people have their vision corrected by wearing

concave lens in their eyeglasses.

• Farsighted people have their vision corrected by wearing convex lenses in their eyeglasses.

REFRACTION OF LIGHT

Videos to WatchConvex and Concave Lenses:• Bill Nye: https://www.youtube.com/watch?v=MvUIsetjVck• Video: https://www.youtube.com/watch/?v=JFbefgVfCoM

Lights and Shadows:• http://www.dailymotion.com/video/x3jbc1a • https:// www.youtube.com/watch?v=CqcYzYUY8f0