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# Science Revison Term 1 SH Heat, Light & Sound

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## Eloise B-J

on 22 May 2014

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#### Transcript of Science Revison Term 1 SH Heat, Light & Sound

The Eye
Science
Term 1
Light
Heat
Sound
Meric/Jane- Heat
Rhea - Sound
Sam - Eye
Eloise-Light
Everyone- Equations

What is Sound?
Equations
Sound is a source of energy which is produced by vibrations.
Types of Waves
Transverse Waves
ALRIGHT.
LET'S DO THE EYE FIRST.
BECAUSE SEEING IS
Incident ray - is the ray of light that strikes the surface before reflection, transmission, or absorption.

Angle of Incidence - the angle at which a beam of light hits a surface.

Angle of reflection - the angle that a ray reflected from a surface forms with a normal ray at the reflection point.

Reflected ray - a ray extending outward from a point of reflection.

Angle of refraction - the angle between a refracted ray and a line drawn normal to the interface between two media at the point of refraction

Refracted ray: the change of direction of a ray ( in this case a light ray)

Normal
BELIEVING
This is when a wave carries energy from one point to another point.
The carried
energy (waves) may be traveling horizontally
, but the
particles which create the wave travel vertically
.
A Transverse Wave looks like a wave on a line.
Heat
Heat separates in three sections;
THE EYE
I don't know what to put in here. I mean, you guys obviously know where the eye is. Hang on...

BAM!
What is Light?
Conduction
Busy yourself with studying that diagram while I go think for a while.
A form of energy
Electromagnetic Rays/waves

Longitudinal Waves
Convection
What are the properties of light?
Light Graphs and Diagrams - By Jane
Travels in straight lines
Speed of light: 300,000 km/s
This is a
SOUND WAVE
The
particles move back and forth
in the
same direction of the wave.
This is also known as a
Compression Wave.
Regular Reflection
Diffuse Reflection
NOTABLE PARTS OF THE EYE
The SPEED of Sound!
The denser a substance, the faster sound travels through it.
WHY?
When a substance is dense, it's particles are compressed together tightly - making the vibration spread quicker as they are near each other.
Zoomed in...
The speed of sound in several materials
Heat Diagrams
Particles
near the flame
vibrate more quickly
as they
absorb heat energy
. These
vibrations
, from particle to particle,
conduct heat along the solid
Conduction
SALE!
SALE!
Where does sound go?
Conductors

Sound usually travels through thin walls
It's transmitted short distances most materials
BUT SOUND DOES NOT LAST FOREVER!

THE LENS
Substances that transfer heat easily are known as
conductors
. Metals such as the saucepan are good conductors of heat.
Hard
Surface
(Concrete/tiles)
IS THE CLEAR PART BEHIND THE IRIS THAT HELPS TO FOCUS LIGHT.
- Metals , particularly copper and gold, are god conductors of heat.
THE PUPIL
THE OPENING AT THE CENTRE OF THE IRIS.
THE IRIS
THE COLOURED PART OF THE EYE THAT REGULATES HOW MUCH LIGHT GETS IN BY STRETCHING THE PUPIL.
Hard surfaces
reflect
sound.
The reflected sound is heard as an
echo
.
THE CORNEA
THE OUTSIDE CLEAR PART THAT ALSO HELPS THE EYE FOCUS.
Insulators
Plastic, air, cloth, wood and rubber are all very poor conductors of heat, and sometimes can block heat transfer completely. such substances are known as insulators.
AQUEOUS HUMOR
THIS IS A CLEAR LIQUID THAT IS LOCATED AFTER THE CORNEA AND KEEP THE PRESSURE IN THE EYE.
- wool fibers and the cotton filling inside a ski parka trap air and help prevent eat loss from your body. Animals rely on body fat and thick coat of fur/ feathers.
Where does sound go?
CILIARY BODY
MUSCLES CONTAINED IN THE CILIARY BODY CHANGE THE SHAPE OF THE LENS.
DID YOU KNOW IF YOU HOLD AN ICE CUBE YOUR HANDS WILL GET COLD?!
VITREOUS HUMOR

CLEAR FLUID BETWEEN THE LENS AND RETINA.
SCLERA
WHITE OF THE EYE.
This is because heat flows from your skin into the ice, lowering the temperature of your skin in the process. You know that the ice cube is absorbing this heat because it starts to melt.
RETINA
THE RETINA IS A THIN, LIGHT SENSITIVE TISSUE LINING THE BACK OF THE EYE. LIGHT MUST BE FOCUSED ONTO THE RETINA.
Echoes aren't always returned when sound is produced.
Sometimes, materials
absorb
the sound produced and converts it to
heat
.
The length of time that the sound can be hears is then reduced
SO THE SOUND DOES NOT LAST FOREVER!
MACULA
Weesywoo16
Transparent
Translucent
Opaque
Describe this!
almost all light is transmitted through a transparent substance
A clear Image can bee seen through something if it is transparent
This glass orb is transparent
this boat is mostly transparent
E.g
Some light may be reflected, and light that passes through is scattered.
An image seen through a translucent material appears to be fuzzy
e.g
This cup is translucent
tissue paper is also translucent
Light is either reflected from or absorbed by the substance, and no light is transmitted
No image can be seen through an opaque material
e.g
this dice is opaque
this lego is opaque
According to the LAW OF REFLECTION : Angle of Incidence = Angle of reflection
According to the LAW OF REFLECTION :
Angle of Incidence = Angle of reflection
I = R
Soft
Surface
(Carpet/Cushion)
Soft surfaces
absorb
sound.
The sound last for a
shorter time
and no echo is produced.
Frequencies and Pitch
Frequency of a wave
is the number of vibrations each second.
The
more
the frequency, the
higher
the pitch of sound.
The
less
the frequency, the
lower
the pitch of sound.
Frequency is measures in
Hertz (Hz).
Amplitude and Loudness
The
amplitude
is the
height
of the wave.
The
higher
the wave, the louder the sound.
The
shorter
the wave, the
softer
the sound.
Amplitude is measures in
Decibels (Db).
High frequency = High pitch
Low frequency = Low pitch
High Amplitude = Louder
Low Amplitude = Softer
The Range of Frequency
Who can hear what??
Different species have different ranges of hearing when it comes to frequency.
For example, bats and dolphins can hear some sounds with an extremely high pitch whilst us, humans, cannot hear these sounds.
The chart across here portrays the hearing range for some animal species.
SOUND DOES NOT TRAVEL THROUGH A VACCUM!
Equations of the Waves
Speed
Frequency
Wavelength
Speed = Frequency x Wavelength
Frequency = Speed ÷ Wavelength
Wavelength = Speed ÷ Frequency
Distance
Speed
Time
Distance = Speed x Time
Speed = Distance ÷ Time
Time = Distance ÷ Speed
Relationships
As frequency increases, wavelength decreases and the speed is constant.
As speed increases, wavelength increases and the frequency is constant.
Equation EXAMPLE.
If the bat sends out a burst of sound which bounces off a tree and 0.2 seconds later returns to the bat, how far away is the tree?
*
Speed of Sound = 330 m/s

Time = 0.2/2=0.1 seconds

Distance = Speed x Time
= 330 x 0.1
= 33m away

*For this question ONLY, assume the speed is 330m/s
You divide it by 2 because the distance
to and from
the tree is 0.2 seconds away.You just want to see the distance
to
the tree -
not to and from.

Therefore, the tree is 33 meters away.
This is HEAT CONDUCTION
Convection
As air

warms

up
,
it becomes less dense and is pushed up by

cooler

air
that is sinking
.
These

convection currents

from the open fire through the air in the room.
~~~Convection Currents~~~
Insulators
Basic Stuff on Insulators
Plastic
,
air
,
wood
,
cloth
and
rubber
are very
poor conductors of heat
, and can sometimes
block heat transfer c o m p l e t e l y
. Such substances are called
Insulators

See this saucepan handle?
insulating materials
! This makes it easier for you to hold the handle without burning your hands.
Gases are poor conductors of heat
Air
trapped by woolen blankets and jumpers help
insulate our bodies from losing heat
, especially in the
cold
.
Similarly,
animals
that
live in cold climates

that help them
stay warm
Pictures!
Wool fibres
and
cotton filling
inside this ski jacket
trap air
and
helps prevent heat loss
Penguins
have a
layers
of fat
and
feathers
, that
fluff up to trap more air
Polar Bears
rely on
body fat
and a
thick coat of fur
for
insulation
Diagrams
heat in the form of electromagnetic waves, which can travel though a vacuum

For example, on an sunny day, you can feel the heat from the Sun and the Earth reach you. Heat has travelled through empty space to you.

Radiation transmits heat as invisible waves at the speed of light (approx. 300 000km per second)

The hotter something is, the more heat it radiates
Conduction is a method of
heat transfer in which heat is
passed by vibration of particles
The process of heat transfer
can happen in
3
ways:
Conduction
,
Convection
,
and
When
hits a surface, the heat may be
absorbed
into the surface,
reflected
from the surface or
transmitted
through the surface.
Absorption
Reflected
Transmission
Heat flows from the hotter cup
into the hands.
Hotter substances have particles that are moving at a faster rate than cooler substances. Rapid Jiggling or vibration of the particles in a hot mug of soup makes the particles in a metal spoon vibrate faster too, increasing the temperature of the spoon.
This process of heat transfer by vibrating particles is called
conduction
.
Convection
As air is heated, its particles gain energy and move further apart. This hot air is less dense than cool air, and so it is pushed upwards by cooler air around it. This method of heat transfer is called
convection
, and the air flow it creates is called a convection current.
Fire warms air
Warm air pushed
upwards
Air cooling and sinking
Cooler air flowing in
Transferring heat
from an open fire.
hi
niiiiii

Who thinks animals are
cute
?
ACTUALLY, STUDY THE EAR MORE....
Totally unrelated to science question is:

What does the fox say?
There's a voice-over on one of the slides - TURN UP YOUR VOLUME!
Full transcript