science_notes.docx

8/16/2019 science_notes.docx

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Light

I can identify a wide range of sources of light, including the sun,

various forms of electric lights, ames, etc.

•

Light is a form of energy just like kinetic energy, potentialenergy, 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 visile to the human eye; you can!t see it.

• Light travels from a light sources "i.e. solar, natural, andman-made#. The temperature of these light sources is $%T.

• &ome ojects emit their own light and others re'uire an

e(ternal source of light to e seen.

• &omething 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.

•

*ou cannot look at right light as it can damage her eyes.• +hen light ounces o a shiny)smooth oject it creates a

reection.

• +hen light goes through a prism-like oject "clear,

glass)plastic)many layers# the light ends and creates

dierent colours of the rainow "dispersion of light#.

Objects that Emit Light (Man-made)


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Objects the Emit Light (Natural)

Observations

• The sun)ashlight or any source of light emits light and hits

an ojects which will then reect light o that oject.

• The characteristic)'ualities "i.e. colour, te(ture, rightness,

etc.# all play a role in the intensity of the reecting light and

the intensity of the reection.

• %jects can also reect light if they are light in colour, shiny

or clear and they don!t reect as much light as they get

darker.

•

The type of material also aects the intensity of thereection of light "i.e. a glass or mirror is clear and it will

reect light rightly or clearly versus a plastic material or a

non-shiny metal which will not reect light as clearly or

rightly.


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Sources of Light

atural Light an-made Light

&un Tra/c Lights

0ireies 1ar lights)headlights

atural 2re "i.e. forest 2re# 0ire "i.e. match sticks, lighters,

etc.#

Sunlight Safety

• 3iewing the sun without proper e'uipment can result in

permanent eye damage. &unglasses, inoculars, andtelescopes do not provide ade'uate protection from direct

oservation of the sun.

• 4dditionally, never look directly at a source of light, whether

it!s man-made and natural.

• &afe to view the sun5 +elder!s glasses availale in hardware

stores.

What does it mean

• +hen an oject emits light it means that it can produce a

discharge of light whether it!s man-made or natural "i.e.

ashlight 6 manmade, lava 6 natural#.

• +hen an oject reects light, it ounces o an oject. If the

surface is smooth and shiny "like glass, water or a polished

metal#, then the light is right and the reection is a

stronger. In comparison to light reecting o dark ojects. In


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other words, when an oject does not emit its own light, it

must reect.

!e"ection of Light

!e"ection

• To ounce o of a surface. 0or e(ample, light

that ounces o a mirror.

• +hen light ounces o an oject and creates

a reection.

• The oject has to e good reector to create

a good reection. 4 good reector appears to

e smooth and)or shiny ecause it reects light evenly and

in one main direction. 0or e(ample, mirrors, calm lake, and

polished metals.

!efraction

• The ending of a light ray as it passes through one oject toanother.

• +hen light rays end as they pass from one oject to

another.


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• 0or e(ample, when light passes through a prism "clear

glass)surface# then the light rays end and produce light.

• Light travels through a light source and passes through a

glass owl full of water. This owl can act as a prism ecause

it has many layers of something.

• 7ecause of the light refracts in water, you can sometimes

not tell the e(act position of an oject underwater. &o, if you

are standing at a dock and looking at 2sh in the lake, the 2sh

underwater don!t always appear to e where actually is.

#ood

!e"ectors

(somethin

g shiny)

$ad

!e"ectors

(somethin

g rough)

&teel water

ottle

7lanket or

any cloth

etal

legs)suppor

t of a chair

+all

"mostly

dark

colours#

etal part

of a

scissors

8ravely

path

Icy)fro9en)c

alm ody of

water

:encil)ack

pack

irror 7oulder)roc

k

1 %ld)dull

1halkoard

1oins %ld)dull

wooden


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ench

&e'uins &ilicone plant pots

!ainbo%

• ature!s display of the spectrum of colours produced y the

dispersion "spreading# of colours as light passes through the

sky during a rainstorm. roplets producing speci2c colours

lie in arches of a circle across the sky which is why the

rainow takes the shape of an arc.

•


7/12

• 7lue with *ellow = 8reen

• *ellow with . 0ireies and Lantern 0ish ":hysiological#

?. Luminous paint; glow in the dark eect 6 which contains

9inc sul2de activated y copper "1hemical#

'he Moon and the Sun

• oes the moon produce light@

• The moon does %T produce light. The moon is a

reector and reects sunlight. The moon!s surface is allrock.

• oes sun produce light@

• The sun is the iggest natural producer of light in our

gala(y.

• +hy does the moon shine@ $ow is it that we see the moon@

• It reects sunlight and it makes the moon shine.

• $ow is it that we see anything that does not produce light@


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• 7asically, everything that doesn!t produce light is a

reector of light or we can only see it ecause it reects

light.


9/12

Transparent Translucent %pa'ue

• &ee

through

or clear

• 4ll light

goes

through

A(amples5

-:lastic +rap

-8lass

+indow

-1lear tape

-1lear)see-

throughglass doors

or windows

-1lear plastic

Biploc ag

• &ome light

goes

through

• Cind of see-

through

• In themiddle

• 1an create

a shadow

when light

shines on it.

A(amples5

-+a( :aper-Lampshade

-Light

coloured)materia

l cloth

-:lastic part of

&igns

-:atterned coverson ceiling lights

and wall lights

-Thick

plastic)clear

inders

-Layers of onion

• ot see-

through

• o light

goes

through

• 1ancreate a

shadow

when

light

shines

on it.

A(amples5

-1ardstock orthick paper

-+all

-Lockers

"metal#

-Thick carpet

-&tairs

-$ook

-0loor

-+ood


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What is a shado%

• 4 shadow is a dark area or shape produced y a ody

coming in etween the rays of light and a surface. %ther

words to descrie the word shadow are silhouette, outline,

shape, pro2le, contour, etc.

• &hadows fall in the %::%&ITA direction of the light source

shining on an oject.

• &hadows change their direction and shape5

>. +hen the sun rises from the east, the shadow is long

and fall on the opposite side of the oject.

?. +hen the sun is in the sky during midday ">?5DDp.m.#,

the shadow was under or all around the oject and it

was shorter.

E. +hen the sun is in the sky during the evening and close

to sunset, the shadow is on the opposite side and it

longer again.

MO!E $O' S*+OWS

• oes the si9e of a shadow change throughout the course of a

day@ *es it change to a dierent si9e and position.

• A(plain how and why have the shadows changed@ &hadows

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

day.

• +hat is the path of the sun@ The sun rises from the east and

sets in the west.

• +here will your shadows fall in the evening@ It will e longer

and almost fading into darkness.


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Shado%s , the Sun

orning &un 4fternoon &un Avening &un

-&hadows are

longer in the

morning

-&un rises from

the Aast

-Time5 Aarly

orning

-&un is the

highest in the

sky

-&hadows fall

directly down

-&hadows get

shorter as the

sun is higher in

the sky.-Time5 idday

-&hadows are

long

-&un sets in the

+est

-Time5 Late

4fternoon

-The shadows

are longer again

as the sun setslower in the sky.

&onve Lens

• 1onve( lens ends outwards or is curved out.

• 4 conve( lens refracts "ends# light.

• +hen eams of light pass through a conve( lens, they comecloser together "converge)meet# to a common point. This

point is called a focus. +hen you place an oject etween

the focus and the lens, the oject will appear magni2ed

"igger#.

• +hen you place the oject away from the focus point, you

will see an upside down image.

&oncave Lens

• 1oncave lenses cause light to spread out "diverge#.

• Things appear smaller through a concave lens.

• earsighted people have their vision corrected y wearing

concave lens in their eyeglasses.


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• 0arsighted people have their vision corrected y wearing

conve( lenses in their eyeglasses.

!E.!&'/ON O. L/#*'

0ideos to Watch1onve( and 1oncave Lenses5

• 7ill ye5 https5))www.youtue.com)watch@v=vFIsetj3ck

• 3ideo5 https5))www.youtue.com)watch)@v=G0efg3f1o

Lights and &hadows5

• http5))www.dailymotion.com)video)(Ejc>a

• https5)) www.youtue.com)watch@v=1'c*9*F*HfD
https://www.youtube.com/watch?v=MvUIsetjVckhttps://www.youtube.com/watch/?v=JFbefgVfCoMhttp://www.dailymotion.com/video/x3jbc1ahttps://www.youtube.com/watch?v=CqcYzYUY8f0https://www.youtube.com/watch/?v=JFbefgVfCoMhttp://www.dailymotion.com/video/x3jbc1ahttps://www.youtube.com/watch?v=CqcYzYUY8f0https://www.youtube.com/watch?v=CqcYzYUY8f0https://www.youtube.com/watch?v=MvUIsetjVck

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