Year 9

Ms Gibellini

SLOs

SLO

Define Energy

Name common forms of Energy

EnergyWhat is energy? Can we see it? What does it do?

Energy is the ability to do work

We cannot see energy but substances and objects can have energy

All energy originally comes from the sun

you have energy from your food and you use it to grow and move and think

a moving car has energy from petrol and they use it to move

radios from electricity and it uses it to make a sound

a glowing torch has energy from chemicals in a battery and it uses it to make light

Types of Energy

/Stored /Active

Success Criteria Complete cut and paste of Energy Types

Complete Sci pad page 74 Introduction to Energy

List five things that energy can do?

Powers appliances, causes movement, creates light, heat and sound

Where does all energy come from?

SUN!

Where do you get energy for your body from?

The food we eat – CHEMICAL ENERGY

SLODescribe energy Transformations

Describe the Law of Conservation of Energy

Law of Conservation of Energy

Energy can neither be created nor it is destroyed, however energy

can be converted from one form of energy to any other form of

energy

Energy ChangesTo describe an energy change for a light bulb we need to do 3 steps:

Electricity Light + heat

1) Write down the starting energy:

3) Write down what energy types are given out:

2) Draw an arrow

What are the energy changes for the following…?

1) An electric fire

2) A rock being dropped from a cliff

3) An arrow being fired

Energy ChainsWhat are the energy changes for the following…?

1) An electric fire

Electricity Heat + light

1) A rock dropping from cliff

Gravitational kinetic sound + heat

1) An arrow being fired?

Elastic + gravitational kinetic heat + sound

Energy ChainsItem Energy

InEnergy Out Energy Chain

Balloon Car Elastic Kinetic, sound, heat

Dinosaur

Bow and Arrow

Solar Light

Yo yo

Mouse trap

Slinky

Cap bomb

Item Energy In Energy Out Energy Chain

Windmill

Tuning fork

Ball

Teeth

Fan

Cars

Shaker

Item Energy In Energy Out Energy Chain

Windmill Kinetic kinetic + heat

Tuning fork Kinetic kinetic + sound + heat

Ball Grav. kinetic sound + heat

Teeth Kinetic elastic sound + heat + kinetic

Fan Chemical electrical kinetic + heat + sound+ light

Cars Kinetic elastic kinetic + sound + heat

Shaker Grav. + kinetic sound + heat + kinetic

Race Car Kinetic Chemical electrical sound + heat + light

Success Criteria Complete worksheets on energy chains

Where does all energy originate from?

SUN

Draw an energy chain for the human eye.

Light energy electrical energy chemical energy

Describe the energy transformations taking place as a plane takes off

Chemical electrical kinetic + sound + heat gravitational + sound and heat

Complete page 79 of Sci pad Energy Transformations and 77 energy changes in an engine

SLODescribe energy efficiency and calculate

efficiency of appliances

Energy Efficiency We know that not all energy is used by appliances:

E.g. Light bulb

Electrical energy Light energy + heat energy

Light energy is useful energy, but in the case of a light bulb heat energy is wasted energy.

Question:

Give an energy transformation for an electric stove element.

Name the useful in an electric stove element.

Name the wasted energy in an electric stove element.

Walnut EnergyThe scientific unit for energy is the joule (J).

1,000 J = 1kJ, kJ = kilojoules

If you heated 1 ml of water by 1’C, then the water would gain 4.2 joules of heat energy.

We can use this to figure out how much energy 1 peanut has in joules.

Walnut Energy

Aim: To find out how much energy is in a walnut

Method:

Results:

Energy Supplied by Peanut: B-A

Conclusion:

Which food had more energy in it?

walnut

Write an energy chain for these experiments.

Chemical heat + light

Not all the energy is used to heat the water, what is it wasted as?

Light energy

Food Temp AfterA

Temp BeforeB

Change in TempA -B

X 42Energy in Joules

Walnut

Marshmallow

Jelly bean

We use the following equation:

USEFUL ENERGY = ENERGY INPUT – WASTED ENERGY

From this we can calculate the ENERGY EFFICIENCY of an appliance:

ENERGY EFFICIENCY = USEFUL ENERGY X 100

ENERGY INPUT

This gives us the energy efficiency as a percentage %.

e.g.

A radio is supplied with 3500J of electrical energy. 3000J is released as sound energy; the rest is lost as heat energy.

What is the energy efficiency of the radio?

Step 1: Write out the information you have:

Energy Input = 3500J Useful Energy = 3000J Wasted E = 500J

Step 2: Write out the equation:

ENERGY EFFICIENCY = USEFUL ENERGY X 100ENERGY INPUT

Step 3: Substitute in the numbers from Step 1:

ENERGY EFFICIENCY = 3000J X 100

3500J

ENERGY EFFICIENCY = 85.7 % round up to 86%

Questions:1. A light bulb is supplied with 60J of electrical energy every second. It transforms about 20J into light and the remaining 40J into heat. What is the energy efficiency of the light bulb?

2. An electric motor transforms 1600J of the 2000J is supplied with into useful work. The rest is dissipated as heat. How efficient is the motor?

3. A car, when supplied with 250kJ of energy, converts 75kJ into kinetic energy in the engine, the rest is dissipated as heat and sound energy. What is the energy efficiency of the car’s engine?

4. An electric hairdryer is supplied with 4500J of electrical energy. 3000J of this energy is released as heat and kinetic energy to dry hair with, the rest is released as sound and some light. What is the energy efficiency of the hairdryer?

Success Criteria Complete pages 76 of Sci pad wasted energy

For every 100 Joules of energy used by an electric light bulb you get only 15 Joules of light energy.

a) What happened to the other 85 joules of energy?

Wasted as heat energy

b) What is the % efficiency of the light bulb?

Eff = useful/total energy x 100

= 15/100 x100

= 15 %

SLODefine a wave and describe two common

forms

Light and Sound waves Light travels in a straight line

Sound is a vibration, longitudinal wave

Light travels faster than sound,

Sound =770 miles per hour

650,500,000 miles per hour in air

lightening and thunder

Fireworks

Types of WavesTransverse Waves:

Light, up and down or side to side

Longitudinal

Sound waves

vibrations are along the same direction as the direction of travel. (in and out)

Vibrations How are sounds made?Particles moving (vibrating)

How does sound get from the source (say, the teacher's mouth) to your ears?

By vibrating air particles moving from the source (mouth) to your ears and banging into your ear drum

How can we stop sounds?Stop vibrating, stop particles from reaching your ears (ear muffs), soft furnishings to absorb sounds (vibration) and stop them reflecting back into the room

Sound waves cannot be heard in space (vacuum, no particles) because….?

Need particles to vibrate, no particles in space!

Success Criteria Complete scipad page 78

How are sound waves made? What do they need?

When something vibrates, they need a medium (gas, air) to move through. Need particles to vibrate.

What type of wave are sound waves?

Longitudinal

What type of wave are light waves ?

Transverse

SLOIdentify the amplitude, frequency and

wavelength of waves

Define and describe sound waves in terms of pitch and loudness

Waves

Amplitude and Frequency

Pitch = Frequency Pitch is determined by the

wavelength

The number of wavelengths passing a point every second is called Frequency, measure in Hertz

Longer the wavelength – lower the pitch

Shorter the wavelength – higher the pitch

Loudness = Amplitude The amplitude of a sound wave is related to the

energy (loudness and softness) that the wave carries, measured in decibels.

The stronger the vibration the greater the sound energy

Reading waves

Wave Pitch (high/Low) Loudness(loud/quiet)

A

B

C

D

Reading waves

Wave Pitch (high/Low) Loudness(loud/quiet)

A Low loud

B Low Quiet

C High Loud

D High Quiet

Reading waves

Wave A and B have the same frequency, but A is louder.

Waves A and B have the same pitch.

Waves C and D have the same frequency, but C is louder.

Waves C and D have the same pitch.

25/01/2015

Using an oscilloscope1) Quiet sound, low frequency:

2) Quiet sound, high frequency:

3) Loud sound, low frequency:

4) Loud sound, high frequency:

Success Criteria Complete pages 78-81

What affect does increasing the amplitude have on sounds?

Louder

What effect does increasing the frequency have on sounds?

Wavelength is shorter, sound is higher pitched

How does changing the pitch effect sounds?

Lower or higher depending on wavelength

Draw a labelled diagram to show a wavelength and amplitude on a sound wave.

How do we calculate Hertz?

Number of wavelengths passing a point every second

SLO

Draw the basic structure of a human ear

What did the receiver say to the radio wave? Ouch! That megahertz.

25/01/2015

How sound travels…As we know, sound waves are formed when something vibrates. But how does the sound reach our ears?

1) An object makes a sound by vibrating

2) The vibrations pass through air by making air molecules vibrate

3) These vibrations are picked up by the ear

Air molecules

25/01/2015

How does the ear work?1) Sound waves are “funnelled” into the ear by the pinna

4) These vibrations are turned into electrical signals in the cochlea2) These

vibrations make the ear drum vibrate

3) These vibrations make the ear bones vibrate

5) The electrical signals are then sent to the brain

Ears and Hearing

The Ear

Hearing Something vibrates and creates a sound wave. The sound wave travels to the ear and is collect by the outer ear. The sound wave then moves into the ear canal. When it reaches the end of the ear canal, the sound waves bump up against

the eardrum. The ear drum vibrates with these sound waves. The vibration moves tiny bones in the middle ear. These bones carry vibrations into the inner ear to a fluid-filled tube called

the cochlea. The fluid inside the cochlea vibrates a series of tiny hairs called cilia, which

are attached to auditory nerves. The movement of these cilia stimulates the nerve cells, and they send

signals to the brain via the auditory nerve. The brain processes these signals into the sounds we hear

Success Criteria Complete Scipad pages 78-82 on Waves and Sound

Draw a flow diagram to show how the human ear works (how sounds move from outer ear to brain, and what kind of energy forms they change to)

Hearing Simplified

Sound vibrations enter Pinna ear canal ear drum hammer anvil stirrup semi circular canal cochlea Cilia nerve brain

SLODescribe some properties of light

and give some examples

LightMake a list of all the things that we use light for

help us see things,

can burn us,

creates rainbows,

helps plants produce food – photosynthesis

helps us take photos

reflects - mirrors

can be hot or cold

Properties of light

The light has three distinctive properties:

moves in a straight line.

It reflects when it reaches a reflecting surface.

Changes direction as it passes from one medium to

another (is refracted).

Sources of LightList as many sources of light as you can.

Light sources can be grouped:

Incandescent Sources: Light produced by heat. flame light bulb sparks bar heater stars lightning

Cold Light: glow worms, fire flies phosphorescence – TV monitors, fluorescence tubes fluorescence – clock faces, glow in the dark things luminescence

Reflected LightThe moon reflects the suns light, it does not emit it is own light.

We see other objects that are not light sources, because light rays from other sources bounce off them in all directions. ( Light is reflected)

Success Criteria Complete scipad 83 - 84

SLODraw ray diagrams and use them to

explain shadows

BBC BBC bitesize

Puppet clip

Shadows A region without light is called a shadow.

The shape of the shadow may not be identical to the shape of the object because the shadow’s shape depends on the position of the light source and on where the shadow falls.

The size and intensity of the shadow depends on the size of the light source and the distance between the light source and the object.

Success Criteria Make a shadow head of yourself, make it a big warped

so it looks funny by playing with the angles

Complete page 85-86 of scipad

http://www.youtube.com/watch?v=NZ5MJqB9myA

SLO

Observe reflection and use the Laws of Reflection to explain observations

Measure and record angles

Identify and make predictions from patterns in data

Reflection What is it about objects that let us see them?

Why do we see the road, or a pen, or a best friend?

If an object does not emit its own light (which accounts for most objects in the world), it must reflect light in order to be seen.

Reflection The angle of reflection always

equals the angle of incidence.

The normal is an imaginary line at right angles (90 degrees) to the point where the incident ray hits the mirror.

Drawing Ray Diagram Rules Ruler

Pencil

Straight lines, with arrows

No sketching

Lines on back of mirror

Light box at correct angle

Correct number of rays

Success Criteria Complete Page 87 of scipad

SLO

Describe various uses of reflective surfaces

Observe the effect of convex and concave mirrors on rays of light

Uses of Reflective Surfaces Where are mirrors used?

Periscopes

Cars

Satellites

Fibre optics

photography

How are they used? Video

Curved Mirrors Concave mirrors cause the light rays to converge

together:

Convex mirrors cause light rays to diverge

Rays and AnglesIncidence Ray

Reflected Ray

Success Criteria Complete scipad page 89-91

Build a periscope, draw a labelled diagram to show how it works on the outside of the box

Video

SLO

Observe refraction and explain your observations

Investigate refraction in lenses of various shapes

Refraction Put the coin in a beaker, hold a ruler

vertically on a bench.

Put your eye at the zero mark on the ruler and get your partner to move the beaker away until you can see to coin (over the lip of the beaker).

Slowly add water to the beaker, what happens to your view of the coin?

Move your eye down towards the bench until you can see the edge of the coin again.

How far down did you have to move?

What has happened? Why?

Refraction The bending of light is called refraction.

Light bends when it passes through substances of different densities. (air to water, air to glass)

The more dense a substance the more it bends

Refraction In Lenses

Lenses Lenses are curved pieces of

glass or plastic

Convex lenses cause rays to converge (come to a point)

Concave lenses cause rays to diverge (go away from each other.

Success Criteria What is the difference between refraction and

reflection, draw a diagram to illustrate your answer.

Reflection – light rays bounce off,

Refraction the light rays are bent as they go from one medium to another

Complete pages 92-95 of Scipad

SLO

Investigate the appearance of coloured objects

Dispersion of Colours Visible or White light is made up of 7 different colours

ROYGBIV

Different colours have different wavelengths (distance between two peaks)

Dispersion of colour We can split white light into its different parts using a

prism, this is called Dispersion. (water can do this to form a rainbow)

Different colours have different wavelengths so travel at different speed through glass or water, therefore they refracted (bent) different amounts, and therefore dispersed (spread out).

Seeing colour Why is a leaf green, milk white and a

tomato red?

When white light hits an object most wavelengths are absorbed, the one colour that is reflected is the colour of the object

A green leaf reflects green light and absorbs all other colours, hence it appears green

Seeing colour Explain why milk is white

and a tomato is red.

Milk reflects all colours, so appears white

Tomato absorbs all colours except red, it reflects red to your eye so looks red!

Mixing Colours Red, yellow and blue are called the primary colour

lights.

We can use these three colours to make many different colours.

Light Practicals White light is made up of a mixture of colours

(ROYGBIV). A coloured filter will let through some of the colours and stop others.

Which filters will let through? Red – red, magenta

Green –Green, cyan

Blue –blue, magenta, cyan

Yellow –yellow

Magenta (red and blue) –Red, blue

Cyan (blue & green) – Blue, green

Predict what colours will get though when:

Light that passes through a primary red filter hits a primary blue filter. - magenta

Light that passes through a primary red filter hits a primary green filter. black

Light that passes through a primary green filter hits a primary blue filter. cyan

Now carry out experiments to test your predictions.

Success Criteria Complete scipad pages 100-102

When white light passes through a green filter what colour do we see?

green

What do we see when we shine red light onto blue paint?

Magenta

Why do leaves look green?Because white light is made up of ROYGBIV and leaves absorb ROYBIV and reflect Green light to your eyes!

SLO

Describe the basic structure and function of the human eye

Structure of the Eye

How our eyes work

Light enters the eye through the cornea and pupil

The light is focused onto the back of the eye (retina) by the lens

The retina is covered in light sensitive cells called light receptors

The receptors change the light energy into electrical energy and a message is passed from the optical nerve to the brain

http://www.e-learningforkids.org/Courses/Liquid_Animation/Body_Parts/Vision/index.html

How we See

Seeing Colour Cones see colour

Humans have three different types of cones, red, blue and green

Success Criteria Complete page 96-99 of scipad

Describe the following terms, use diagrams to help: colour blindness, short sighted, long sighted

Revision https://www.youtube.com/watch?v=CbkaL-vgiKI