Loading presentation...

Present Remotely

Send the link below via email or IM

Copy

Present to your audience

Start remote presentation

  • Invited audience members will follow you as you navigate and present
  • People invited to a presentation do not need a Prezi account
  • This link expires 10 minutes after you close the presentation
  • A maximum of 30 users can follow your presentation
  • Learn more about this feature in our knowledge base article

Do you really want to delete this prezi?

Neither you, nor the coeditors you shared it with will be able to recover it again.

DeleteCancel

Y8 Light & Sound - KS3 Science

Seeing Light - Reflection - Refraction - Coloured Light - Coloured Filters - Sound Waves - Travelling Sound Waves - Hearing Sound - Damaging Hearing
by

J Amuah-Fuster

on 8 July 2016

Comments (0)

Please log in to add your comment.

Report abuse

Transcript of Y8 Light & Sound - KS3 Science

Y8: Light & Sound
The Pinhole Camera
Sort objects in luminous and non-luminous

Describe how we see things

Explain why we get shadows
Lesson Outcomes
To finish....
Sort the objects into
translucent
,
transparent
,
opaque

Sort the objects into
luminous
and
non-luminous
How do we see the candle?
Decide who you agree with
Transparent
material lets
almost all light
pass through.

Translucent
material only allows
some light
through.

Opaque
material
does not allow light
to pass through.
Light waves travel in
straight
lines.
Conclusions
What is light?
Light waves travel in
straight lines
.
Light travels at a speed of
300,000,000 metres per second
, which is much
faster than sound
(330 m/s in air).
Light
carries energy
and travels as a
wave
.
Non-luminous objects

Luminous objects

A luminous object is one that produces light.
A non-luminous object is one that reflects light.
Luminous and non-luminous objects
Optic Nerve
An object that does not give out light is non-luminous.

How does light from a luminous object such as a light bulb reach the eye?

How do we see things?
Light travels in a straight line directly into the eye.

An object that gives out light is described as luminous.

Light from the light source hits the book and some of this light is reflected into the eye.
How does your eye see a non-luminous object such as a book?

Why can you see your reflection in the mirror and not in the table?
Reflection Investigation
Investigate the link between the
angle of incidence
and the
angle of reflection

Describe the type of surfaces that make good and bad reflectors of light

Explain the differnce between
clear
and
diffuse
images and how they are fromed
Bad reflectors are usually
dark
colours.
Lesson Outcomes
In other words, light gets reflected from a surface at ___ ____ angle it hits it.
the same
Angle of incidence
=
Angle of reflection
The Law of Reflection
Diffuse
reflection is when
light is scattered
in different directions
Smooth
,
shiny
surfaces have a
clear
(regular) reflection
Clear vs. Diffuse Reflection
Reflected ray
Incident ray
Reflection from a mirror:
8. TORCH
7. MIRROR
2. MOON
1.BULB
3. DIAMOND RING
5. STAR
6. CANDLE
4. SUN
Sort the pictures into 2 groups.
What criteria have you used to sort them?
Worst Reflectors
Best Reflectors
Tarmac Road
Green Leaf
Tangerine
Blue Car
Yellow Banana
Al foil
White Paper
Reflection : Good or Poor?
Tree Bark
Polished Black Shoes
Starter
Regular
reflection gives clear images because light is
reflected regularly
.
Headlight
Use what you learnt about refraction to explain
in detail
one of the images you saw at the beginning of the lesson.
Plenary
The ray bends outwards, away from the normal, to the first direction again.

The ray travels through the air until it hits the glass.

The ray bends inwards, towards the normal line.

A straight ray of light leaves the ray box.

The ray travels through the air in a straight line.

The ray travels straight through the glass until it reaches the edge
Refraction:
Can you put the statements in order?
What happens when the ray enters the block at 90º?

What happens when the ray enters the block at any other angle?

What happens to the ray that entered at 90º when it leaves the block?

What happens to the other rays when they come out of the block at any other angle?

Compare the direction of the ray entering the block with the direction of the ray coming out of the block.
What do you notice?
Considering the evidence
The light had been
refracted
by the water:
State what
refraction
is.

Draw labelled diagrams showing the refraction of light.

Explain the link between the
angle of incidence
and the
angle of refraction
Lesson Outcomes
Can you explain what is happening in these pictures?
4. This side of the ray reaches the outside first and
speeds up
through the air.
The beam
bends

outwards
again.
Equipment
:
ray box with a single slit
glass block
ruler
low voltage power supply
white paper
Refraction: Practical instructions
3. The whole beam

bends inwards
.
2. This side of the ray reaches the block first and is
slowed down
by closely-packed particles in th block.
1. Light hits the glass block.
This change in direction is called
refraction
.
…but it still travels in straight lines.
When light passes from one medium to another...
Light travels in straight lines.
What are
secon
dary c
olours
of light?
State the colours that white light can be split into.

Explain how to get white light from coloured light.

Explain how we see colours of objects.
Lesson Outcomes
What are
prim
ary co
lours
of light??
Think,
How is a rainbow formed?
True or false?
1. White light is made up of 10 colours.

2. Violet light is refracted more than any other
colour of visible light in the spectrum.

3. A spectrum is a dispersion of colours.

4. Prisms put colour into light.

5. Indigo is a dark pink colour.
White light is
not a single colour
; it is made up of a
mixture of colours
found in the rainbow.
Colour
Complete the table
Shirt looks red
Shorts look blue
White light
If we look at a coloured object in coloured light we see something different. For example, consider a football kit:
Using coloured light
Red light
In different colours of light this kit would look different:
No light reflected - Shorts look
black
Shorts look
blue
Shirt looks
red
Adding
red
,
blue
and
green
makes
white
again
Adding
blue
and
green
makes
cyan
(light blue)
Adding
red
and
green
makes
yellow
Adding
blue
and
red
makes
magenta
(purple)
White light can be
split up
to make separate colours. These colours can be added together again in differnt combinations.

The
primary
colours of light are
red
,
blue
and
green
:
Adding colours
L3:Refraction
L2: Reflection
L1: Seeing Light
L4: Coloured Light
How
do
you see the flower?
STARTER
Rough
,
dull
surfaces have a
diffuse
reflection.
Good reflectors are usually
pale
colours.
What do you notice about the
angle
of the incoming light compared to the reflected light?
What happens?
Place a coin inside a cup sitting on a table.

Move the cup away from you so that the coin just leaves your sight.

Fill the cup with water.
The Invisible Coin
Why?
Obtaining evidence
Set up the apparatus as shown in the diagram on your sheet.

You are going to
draw light rays going into
and
coming out of the glass block
for each of the following angles:
45º
135º
90º
70º
Refraction:
Key Facts
...it may change direction...
...the
smaller the angle
of refraction
The
more dense
the medium...
Starter
What are the
7
colours of the rainbow?
Can you think of a way to remember the
order
of the colours?
Share
Pair,
Blue light
No light reflected - Shirt looks
black
We say that
yellow
,

magenta

and

cyan
are
secondary
colours
L5: Coloured Filters
Sort the cards into true and false
True/False?
Write down the 3
primary
colours of light.

Write the names of the 3
secondary
colours of light.

What colour do we get when all the
colours of light mix
together?



Think of everything we have learnt about light and colour so far.

Come up with a quiz question and write it onto your post-it note.

Write the answer at the back.
C
o
l
o
u
r

q
u
i
z
A green filter will absorb every colour of light except for green.
Coloured filters
absorb
light.

Different coloured filters absorb different colours, except for the colours
transmitted
.
Filtering light
What colour would a red filter let through?
What filter is in this box?
What colours would you see through the following filters?
Draw this in your book.
Using filters
Blue
Green
Red
Using filters
Filters work by
absorbing
some colours and
transmitting
(letting through) others.
Starter
Lesson Outcomes
Yellow
Cyan
Magenta
White
Describe what can happen to light when it passes through a filter

Explain how produce coloured light
4) _____ sound, _____ pitch:
3) _____ sound, _____ pitch:
2) _____ sound, ______ pitch:
1) Quiet sound, _____ pitch:
Using an oscilloscope
Frequency and Pitch
A low pitch sound.
A high pitch sound.
Pitch (or frequency)
Amplitude and Loudness
The
bigger
the waves you can see, the
louder
the sound.
A quiet sound.
Loudness
How can you change a sound?
Discuss with your partner and be ready to share your ideas
What is pitch?
Describe some qualities of sound

Relate changes in
pitch
and
loudness
of sounds to changes in
vibrations

Use the words ‘
frequency
’ and ‘
amplitude
’ when describing vibrations
Learning Outcomes
Write down as many keywords about sound as you can remember from KS2

Write down the definitions if you can
L6: Sound Waves
The height of a wave is called the __________.
Waves with big amplitude are very __________.

The __________ of a wave is the number of waves every second.
A sound with high frequency has a high ________.
Sound wave Rules
Oscilloscope traces

B
’ Is the loudest sound because it has the
largest amplitude
.
The
larger the amplitude
the
more energy
a wave has.
The
more energy
it has, the
louder
the sound.
Which trace represents the loudest sound?

A
’ is the highest pitched sound because it has the
shortest wavelength
or the
most number of waves

visible
during the same timespan,
Which trace represents the highest pitched sound?
Oscilloscope traces
Sound needs particles to be able to travel

Sounds travels fastest in gases

Sound can only travel through gases

Sound can not travel in a vacuum

Pitch is how loud or quiet a sound is
True or False
Sound needs
particles
to be able to travel.
For each of the jars, state whether you would be able to hear the bell and explain using particles.
Bell jar
Describe what the sound would be like for each of the oscilloscope readings below.

Would it be
loud
or
quiet
?
Would the sound be
high pitch
or
low pitch
?

Write the description into your book
L7: Travelling Sound
Starter
Learning Outcomes
Define what is meant by a longitudinal wave

Describe how sound waves travel

Explain why sound can not travel through space
Explain why sound travels
best in solids
using ideas about particles.
You may want to use a diagram to help you
Travelling waves
These vibrations are
longitudinal
waves (the move
left and right
)
Sound waves are passed on as
vibrations
from one particle to another.
What happens to the sound as the air is removed?
Why does this happen?
An ultrasound scan uses high-frequency sound waves, which reflects (bounces off) solid objects
Submarine Sonar
Bats and Dolphins (echo location)
Calculating distances/depths
Identifying objects, e.g. wrecks, shoals of fish
Finding oil, or other rock layers
Sonic imaging to find weld crack etc.
Radar
Acoustic design for music halls.
Think of some examples of how
echoes
can be
useful
and
write a list
in your book.
Why do you think we have two ears?
2 ears or 1 ?
Reflected sound
The sound wave is
reflected
back from the surface.
This is called an
echo
.
Sound and light can both be _________.
A reflected sound is called an ______.
You can often hear echoes near __________
or caves, because ________ is reflected off
_____objects. Echoes can be used to find
out how far away something is.
solid
mountains
echo
reflected
sound
Echoes
echo
mountains
reflected
solid
sound
How does the ear work?
5) The electrical signals are then
sent to the brain
by the
auditory nerve
3) These vibrations make the
ear bones
vibrate
2) These vibrations make the
ear drum

vibrate
4) These vibrations are
turned into

electrical signals
in the
cochlea
1) Sound waves are “
funnelled
” into the ear by the
pinna
Scientists report that teenagers hearing is being damaged by listening to music on headphones and going to loud concerts.
BREAKING NEWS!
Upsets
the
electrical signals
to the brain.
What is Tinnitus?
Look at the picture and make a list of sounds that could damage your hearing and sounds not likely to damage your hearing
Sound can damage your ears if it is too _____ or goes on for too long, unpleasant sound is called _____.

The unit of loudness of sound is ___________

The threshold of hearing is the _______ sound we can hear, this is called 0db. A road drill is 90db.

Discos or _________ can often exceed 90db

Sounds start to become ________ at 80db, and the eardrum breaks at 180db
concerts
decibel (db)
loud
noise
painful
quietest
Tarmac Road
Green Leaf
Tangerine
Blue Car
Yellow Banana
Al foil
White Paper
Tree Bark
Polished Black Shoes
Headlight
Best
Worst
Can you explain what is happening in these pictures?
Richard (Red)
Of (Orange)
York (Yellow)
Gave (Green)
Battle (Blue)
In (Indigo)
Vain (Violet)
We can demonstrate this by splitting white light with a prism:
This is how rainbows are formed: sunlight is “split up” by raindrops.
Red
,
Blue
,
Green
are primary colours of light

Magenta
,
Cyan
,
Yellow
(Amber)


White
light is made when we mix all the colours together.
Starter
How can you change the pitch of a sound?
We say this image is
inverted
The
more waves
you can see, the
higher
the
frequency
(number of waves passing every second)

and

the
higher
the
pitch
.
A louder sound.
We can make the pitch
higher
or
lower
:
Higher
- use
smaller
,
shorter
, or
thinner
vibrating objects

Lower
- use
larger
,
longer
, or
thicker
vibrating objects
quiet
high
low
high
loud
loud
low
amplitude
frequency
loud
pitch
Copy and complete the sentences
loud
frequency
amplitude
pitch
Describe the sound waves on the right
The amplitude is how tall the wave is from its mid-line
The
frequency
tells us the number of waves that pass a point over a given time.
The units are
waves per second
or
Hz
(
Hertz
) for short.
Discuss with the person next to you.
Can you think of any advantages ?
L8: Hearing Sound
L9: Damaging Hearing
Tinnitus is the sensation of hearing
ringing, buzzing, hissing, chirping, whistling
, or other sounds.
The noise can be
intermittent
or
continuous
, and can vary in
loudness
.
Make a poster for teenagers to advise them about
how hearing can be
damaged

and

how they can
protect
their

ears
Starter
Hearing Loss
Copy and complete the statements below
quietest
decibel (db)
concerts
loud
noise
painful
How does it happen?
Arrange these items along the arrow:
What happens when a sound wave meets a
hard

flat
surface?
How can echos be useful?
Other examples of useful echos
Dolphins use echolocation to find food
Gongs use echos to spread the sound over a greater area.
Submarines use echolocation to find out where the ground or obstacles are.
Bats also use echolocation to find food
How is a pinhole camera like a human eye?
The
lens
changes the direction of the light rays, helping them to
focus
(meet) at a specific point
How do we make shadows?
To make a shadow you need a
luminous object
and an
opaque
material.
Transparent
Bottle (empty)
Glass
Opaque
Magazine
Mug
Orange juice
Plant
Shower curtain
Teapot
Television
Translucent
Net curtains
Luminous
Television
Non-luminous
Bottle
Glass
Magazine
Mug
Net curtains
Orange juice
Plant
Shower curtain
Teapot
Ear drum
Auditory nerve
Outer ear
Sound waves travelling
Cochlea
Ear canal
Ear bones
Sound waves travelling
Auditory nerve
Ear canal
Ear drum
Outer ear
Ear bones
Cochlea
Prevention
is better than cure!
Affects sleep, and hearing and can be very troublesome.
Damage
to the
hair cells
in the
cochlea
.
How can people lose their hearing?
Reflection
Starter
What happens when light rays hit a glass block at an angle?
What happens when the light beam leaves the block?
Full transcript