BM

Bryndl

​

Connor

Rose

​

​

Simba

EunJu

Tina

​

Chi Phuong

Annie

​

Bean

Ivory

Chi

Kazu

Cherry

​

Danny

SeungWoo

​

Suri

Nathan

​

Amy

Didi

​

P1 Motion

Sit with your partner

1.3.1 Distinguish between mass and weight

_ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _

Sound

What is that sound?

Do Now

Without stopping, Talk for 60 seconds about ………….

​

https://www.online-stopwatch.com/timer/60seconds/

​

P4 Waves

Do Now

sound, light and waves

Use Canva to Create a board game with questions and answers on sound, light and properties of waves. You can use the quizlets, booklet, research and powerpoint

P4 Waves

Do Now

Challenge: Include units and machines that measure and create sound and light

Sound

What is that sound?

Do Now

1.

8.

7.

6.

5.

4.

3.

2.

9.

10.

Rest position

Amplitude – the height of the wave. Measure from rest position to crest or trough

​

Wavelength – the distance from one crest to the next crest (or trough to next trough)

1

2

3

4

P4 Waves

What are the parts of a wave?

4.1.3 State the meaning of speed, frequency, wavelength and amplitude

• Be able to explain how vibrations make sound waves.
• Be able to state the speed of sound in air.
• Know about how sound travels in different mediums (gas, liquid, solid)
• Describe the parts of a wave

​

​

​

​

P4 Waves

By the end of the lesson, I should….

Learning Objectives

1. Everything is made of particles
2. Particles are attracted to each other
3. Particles are always moving
4. When heated, particles move faster

P4 Waves

The 4 principles of the particle theory of matter are:

Starter

There a 3 states of matter:

• Solid
• Liquid
• Gas

Title: The Particle Theory

Before you start:

Use pencil

Particles should be the same size

Particles should not be too big or too small

Show what the particles are doing using arrows and lines

​

​

P4 Waves

Draw a diagram with to show particles in each state of matter

4.4.5 Show an understanding that a medium is needed to transmit sound waves

• Sound is a form of energy that travels as a longitudinal waves
• Sound is caused by vibrations.
• Sound travels at 340m/s. in air. It travels faster through solids because the particles are more dense

​

What do you know about sound?

4.4.1 Describe the production of sound by vibrating sources

P4 Waves

A sound begins with a vibration

P4 Waves

What do you know about sound?

4.4.1 Describe the production of sound by vibrating sources

3 examples of transverse waves:

1. Electromagnetic Waves (Light)
2. String waves (Guitar)
3. Water Waves (Ocean)

P4 Waves

What do you know about sound?

4.4.1 Describe the production of sound by vibrating sources

P4 Waves

What are the two types of waves?

4.1.4 Distinguish between transverse and longitudinal waves and give suitable examples

• Longitudinal Waves – motion of the particles is parallel to the motion of the wave. Sound is a longitudinal wave

​

​

​

• Transverse Waves – motion of the particles is perpendicular to the motion of the wave. Light is a tranvserse wave

​

P4 Waves

Longitudinal Waves

4.4.3 Describe the transmission of sound waves in air in terms of compressions and rarefactions

Challenge: Create 3 questions from the data above

P4 Waves

4.4.4 State that the approximate range of audible frequencies for a healthy human ear is 20Hz to 20000Hz

This shows sound waves carry energy!

Kinetic or potential?

Sound

A sound has moving particles

Demonstration

Sound

In what direction can waves travel?

​

​

​

​

​

​

​

4.4.5 Show an understanding that a medium is needed to transmit sound waves

• The best way to think about waves is as a disturbance that travels through a medium – some substance made of molecules.�
• Because the particles always return to their original position, waves transfer energy without transferring matter.

Yes! Sound travels faster and further through a liquid than it does a gas.

P4 Waves

Can sound waves travel through liquids?

4.4.7 Recognise that sound travels faster in liquids than in gases and faster in solids than in liquids

Challenge: Why?

• Through air 300 m/s
• Through water 1500 m/s
• Through iron 5000 m/s

Think about the density of each state of matter.

P4 Waves

Can sound waves travel through liquids?

4.4.7 Recognise that sound travels faster in liquids than in gases and faster in solids than in liquids

How do waves move?

No!

​

WHY?

​

​

​

There are no particles in a vacuum.

P4 Waves

Can sound waves travel through a vacuum?

4.4.5 Show an understanding that a medium is needed to transmit sound waves

Vacuum, space in which there is no matter or in which the pressure is so low that any particles in the space do not affect any processes being carried on there

• Oscilloscope - An instrument that allows us to “see” and study sound waves. It converts a longitudinal wave into a transverse wave.

P4 Waves

What is an oscilloscope?

4.4.6 Describe and interpret an experiment to determine the speed of sound in air, including calculation

Demo – Oscilloscope & Tuning Forks

Key Words – sound, wave, compression, rarefaction, solid, liquid, gas, air, water, speed, distance, time, frequency, wavelength, amplitude, oscilloscope, pitch, vibrations, Hertz, echo, reflection, particles, density

Task 1 – Drawing Oscilloscope Traces

1. Loud, high pitched tone.

2. Loud, low pitched tone.

3. Quiet, high pitched tone.

4. Quiet, low pitched tone.

Key Words – sound, wave, compression, rarefaction, solid, liquid, gas, air, water, speed, distance, time, frequency, wavelength, amplitude, oscilloscope, pitch, vibrations, Hertz, echo, reflection, particles, density

Loudest sound?

A

B

Key Words – sound, wave, compression, rarefaction, solid, liquid, gas, air, water, speed, distance, time, frequency, wavelength, amplitude, oscilloscope, pitch, vibrations, Hertz, echo, reflection, particles, density

Highest pitch?

A

B

Key Words – sound, wave, compression, rarefaction, solid, liquid, gas, air, water, speed, distance, time, frequency, wavelength, amplitude, oscilloscope, pitch, vibrations, Hertz, echo, reflection, particles, density

Quietest sound?

A

B

Key Words – sound, wave, compression, rarefaction, solid, liquid, gas, air, water, speed, distance, time, frequency, wavelength, amplitude, oscilloscope, pitch, vibrations, Hertz, echo, reflection, particles, density

Lowest pitch?

A

B

Key Words – sound, wave, compression, rarefaction, solid, liquid, gas, air, water, speed, distance, time, frequency, wavelength, amplitude, oscilloscope, pitch, vibrations, Hertz, echo, reflection, particles, density

Loudest sound?

A

B

Key Words – sound, wave, compression, rarefaction, solid, liquid, gas, air, water, speed, distance, time, frequency, wavelength, amplitude, oscilloscope, pitch, vibrations, Hertz, echo, reflection, particles, density

Highest pitch?

A

B

Key Words – sound, wave, compression, rarefaction, solid, liquid, gas, air, water, speed, distance, time, frequency, wavelength, amplitude, oscilloscope, pitch, vibrations, Hertz, echo, reflection, particles, density

How do we hear?

• Vibrations in the air allow us to hear, these exist as compressions and rarefactions.
• Most of the time these sound waves travel through the air.
• The sound waves vibrate various parts of our ear which then produce an electric signal that is sent to the brain.
• Humans can hear frequencies between 20 – 20,000 Hz.

Key Words – sound, wave, compression, rarefaction, solid, liquid, gas, air, water, speed, distance, time, frequency, wavelength, amplitude, oscilloscope, pitch, vibrations, Hertz, echo, reflection, particles, density

Task 2 – Hearing Sound (Peer Review)

• The class next door are being extremely noisy. Describe how we are able to hear the noise. You should talk about the following.

• The particles in the air and the walls.
• The speed of the sound wave through air and the walls.
• How does our ear detect the sound?

• As the students talk they create compressions and rarefactions sending sound waves through the air.
• These travel at 330 m/s.
• When the sound hits the wall its causes the wall to vibrate.
• The sound wave then travels quickly through the wall as the particles are closer together.
• This causes the air on the other side of the room to vibrate and the sound wave slows down as the particles are further apart.
• The sound wave then vibrates certain parts of your ear which then convert it into an electrical signal that is sent to the brain.

Key Words – sound, wave, compression, rarefaction, solid, liquid, gas, air, water, speed, distance, time, frequency, wavelength, amplitude, oscilloscope, pitch, vibrations, Hertz, echo, reflection, particles, density

https://www.youtube.com/watch?v=0Anh9HthWgQ

P4 Waves

Wave Summary Video

Checkpoint

Rest position

Amplitude – the height of the wave. Measure from rest position to crest or trough

​

Wavelength – the distance from one crest to the next crest (or trough to next trough)

1

2

3

4

P4 Waves

What are the parts of a wave?

4.1.3 State the meaning of speed, frequency, wavelength and amplitude

Frequency – how many waves there are determines the Pitch (the highness or lowness of a sound) measured in Hertz (Hz)

P4 Waves

What is pitch?

4.4.8 Relate the loudness and pitch of sound waves to amplitude and frequency

Amplitude is the height of the wave and determines the loudness of a sound measured in Decibels (db)

P4 Waves

What is loudness?

4.4.8 Relate the loudness and pitch of sound waves to amplitude and frequency

Soft

Loud

P4 Waves

What is pitch and loudness?

4.4.8 Relate the loudness and pitch of sound waves to amplitude and frequency

P4 Waves

Longitudinal Waves

4.4.3 Describe the transmission of sound waves in air in terms of compressions and rarefactions

A rarefaction is where particle spacing is maximum

A wave compression is where particle spacing is minimum.

motion of the particles is parallel to the motion of the wave.

P4 Waves

What is a transverse wave?

4.1.4 Distinguish between transverse and longitudinal waves and give suitable examples

A wave crest is where particle distance from its original position is a maximum.�

A wave trough is where particle distance is minimum.

Energy is moving perpendicular (forward) to particles (upwards).

See if you can create several compressions and rarefactions.

P4 Waves

Modelling Sound Waves

4.1.2 Describe what is meant by wave motion as illustrated by vibration in ropes and springs and by experiments using water waves

We could also ask: How many cycles does this wave complete each second?

Frequency – it is the number of cycles completed per second

Frequency is measured in Hertz (Hz)

​

P4 Waves

Calculating the speed of sound waves

4.4.6 Recall and use the equation v = f λ

Rest position

Amplitude – the height of the wave. Measure from rest position to crest or trough

​

Wavelength – the distance from one crest to the next crest (or trough to next trough)

1

2

3

4

P4 Waves

What are the parts of a wave?

4.1.3 State the meaning of speed, frequency, wavelength and amplitude

P4 Waves

Period and Frequency

4.1.3 State the meaning of speed, frequency, wavelength and amplitude

P4 Waves

The speed of sound through different mediums

4.4.7 Recognise that sound travels faster in liquids than in gases and faster in solids than in liquids

P4 Waves

Calculating the speed of sound waves

4.4.6 Recall and use the equation v = f λ

P4 Waves

What is the wave speed?

4.4.6 Describe and interpret an experiment to determine the speed of sound in air, including calculation

Example 1

Example 2

P4 Waves

What is the wave speed?

4.4.6 Describe and interpret an experiment to determine the speed of sound in air, including calculation

P4 Waves

Worked Examples

4.4.6 Describe and interpret an experiment to determine the speed of sound in air, including calculation

P4 Waves

Examples.

4.4.6 Recall and use the equation v = f λ

P4 Waves

Examples.

4.4.6 Recall and use the equation v = f λ

Amplitude measures how much energy is in the wave.

Big amplitude = BIG SOUND = Loud

P4 Waves

How does amplitude effect sound?

4.4.8 Relate the loudness and pitch of sound waves to amplitude and frequency

Amplitude determines LOUDNESS!

​

​

An amplifier increases the amplitude of sounds.

P4 Waves

How does amplitude effect sound?

4.4.8 Relate the loudness and pitch of sound waves to amplitude and frequency

The pitch depends on how many vibrations there are.

The more frequent the vibrations the higher the note.

The fewer the vibrations the lower the note

P4 Waves

What is pitch and how does it effect sound?

4.4.8 Relate the loudness and pitch of sound waves to amplitude and frequency

P4 Waves

How does amplitude effect sound?

4.4.8 Relate the loudness and pitch of sound waves to amplitude and frequency

​

​

Mouse’s squeak: Low amplitude

High freq

Lion’s roar: High amplitude

Low freq

?

?

?

?

P4 Waves

Fill in the missing words

4.4.8 Relate the loudness and pitch of sound waves to amplitude and frequency

• Individually or in pairs Create a 1 to 2 minute movie on sound.

​

• What types of waves is sound?
• What does this look like?
• How fast does sound travel through solids, liquids and gases? Why?
• What is an oscilloscope?
• What are the 5 parts of a transverse wave?
• What is pitch?
• What is frequency? Units? Give an example of high and low
• What is amplitude?
• What is loudness? Units? Give an example of high and low
• Challenge: How do whales use ultrasound?

P4 Waves

Make a movie

Checkpoint

• When sound hits a medium that is more dense, most of the energy will reflect back, just like light. �
• When we hear a reflected sound after hearing the original, we refer to it as an echo.

​

• The reflection of sound is useful for many animals and technologies

P4 Waves

What is an echo?

4.4.9 Describe how the reflection of sound may produce an echo

The frequency range of humans is from 20Hz to 20,000Hz.

Below 20Hz are infrasounds, above 20,000 are ultrasounds.

P4 Waves

What is hearing range?

4.4.4 State that the approximate range of audible frequencies for a healthy human ear is 20Hz to 20000Hz

• Ultrasounds are sounds that are too high (more than 20,000 Hz) for humans to hear.

What is ultrasound?

P4 Waves

4.4.4 State that the approximate range of audible frequencies for a healthy human ear is 20Hz to 20000Hz

When a sound is made, the air around the sound vibrates.

Hearing starts when some of the sound waves funnel into the ear.

P4 Waves

How do we hear?

Extra Information

P4 Waves

How do we hear?

Extra Information

P4 Waves

How do we hear?

Extra Information

1. Ear flap (Pinna)

2. Ear canal

3. Ear drum

5. Anvil

6. Stirrup

7. Cochlea

4. Hammer

8. Eustachian tube

9. Auditory nerve

P4 Waves

How do we hear?

Extra Information

Nerve cells on the hairs detect this movement.

They send signals to the brain.

You hear the sound.

Tiny hairs – cilia – hang down into the liquid. Vibrations travelling through the liquid push the hairs.

What are the tiny hairs in our cochlea?

P4 Waves

Extra Information

• Loudness is measured in decibels, dB

​

​

Any sound that is unwanted is called noise.

Decibel scale

P4 Waves

Extra Information

Sounds louder than 80 decibels are considered potentially dangerous.

​

Decibel scale

P4 Waves

Extra Information

P4 Waves

Why do we see lightning before we hear thunder?

Do Now

P4 Waves

What is light?

Starter

Light carries energy and travels as a wave.

Light waves travel in straight lines.

Light travels at a speed of 300,000,000 metres per second, which is much faster than the speed of sound.

Light is produced by the Sun, and by objects such as light bulbs and matches.

Summarise this in 5 words or less

Light

How do we see things?

Task 1

An object that gives out light is described as luminous.

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

Light travels in a straight line directly into the eye.

LUMOS!

Make a list of 5 objects that are luminous

Light

How do we see things?

An object that does not give out light is non-luminous. How does your eye see a non-luminous object such as a comb?

Light hits the comb and some of it is reflected into the eye.

Make a list of 5 objects that are non- luminous

1. Circle the luminous sources

​

• Label the luminous sources

​

• Draw how the one-armed man would be able to watch television.

​

• Draw how the man would be able to see the chair.

​

​

​

Light

How do we see things?

Light

How do we see things?

Light bulb

sun

TV

• 1. Light travels in _________________ lines
• 2. Luminous objects ________________________ light
• 3. The Sun is ________________________ because___________________________________________
• 4. Light travels at _________________________ m/s
• 5.Non-luminous objects ________________ the light into our eyes so we can see the object.

Light

Answer the following question in your books

Checkpoint

straight

give out

luminous

It gives out light

300 000 000

reflect

Light

Are all objects the same?

Task 2

Opaque: no light will pass through

​

Transparent: all or most of the light passes through

​

Translucent: some light passes through

• An object that allows all light to pass through it is called………………………………………………

​

• An object that allows just some light to pass through it is called…………………………………

​

• An object that allows no light to pass through it is called………………………………………………
• translucent transparent opaque

​

Leave some space under each one to draw something!

Light

Answer the following question in your books

Checkpoint

1

​

​

​

​

2

​

​

​

​

3

1. Transparent

​

​

​

• Translucent

​

​

​

• Opaque

Match 1 2 3 and A, B, C together!

Transparent – these are materials which let all of the light straight through.

Translucent – these materials let light through but it is randomly scattered.

Opaque – these materials let no light through.

clear glass

frosted glass

wood

wine glass

tracing paper

book

brick

cling film

steel

marble ball

pencil

curtains

cardboard

water

​

Light

Design a table to show whether these objects are transparent, translucent or opaque

Challenge: Can you think of any other objects for each category?

Light

Why do you shadows form?

Task 3

1 Which of these statements is true?

A Light travels in straight lines.

B Light is stopped when it meets a solid object.

C Light does not travel in straight lines.

D Light will only travel for about 2000km before it stops.

Light

Checkpoint

2 Which of these is not a source of light?

A a light bulb

B the Sun

C a mirror

D a TV

Light

Checkpoint

3 Shadows are formed because:

A light will only travel a certain distance before it stops.

B a substance called ‘darkness’ collects behind some objects.

C some objects do not give out light in all directions.

D light cannot go through some objects.

Light

Checkpoint

4 Which statement is true?

A Sound travels faster than light.

B Sound will not travel. Only light can travel.

C Light travels faster than sound.

D Light and sound travel at the same speed.

Light

Checkpoint

5 Objects that light can easily pass through are said to be:

A transparent.

B apparent.

C opaque.

D oblong.

Light

Checkpoint

6 Which phrase best completes the following sentence? We see things because:

A they are luminous.

B the Sun shines on them.

C light from them enters our eyes.

D light from our eyes shines on them.

Light

Checkpoint

7 Opaque objects can:

A transmit and reflect light.

B transmit and absorb light.

C reflect and absorb light.

D only reflect light.

Light

Checkpoint

8 Which of these will absorb the most light?

A a white sheet of paper

B a sheet of clear glass

C a black piece of card

D an orange piece of card

Light

Checkpoint

9. Which of these diagrams show how light rays travel?... There may be more than one that is right!

ANSWERS

​

​

Light

Swap your books to mark each other’s answers.

Checkpoint

1 Which of these statements is true?

A Light travels in straight lines.

B Light is stopped when it meets a solid object.

C Light does not travel in straight lines.

D Light will only travel for about 2000km before it stops.

Light

Swap your books to mark each other’s answers.

Checkpoint

2 Which of these is not a source of light?

A a light bulb

B the Sun

C a mirror

D a TV

Light

Swap your books to mark each other’s answers.

Checkpoint

3 Shadows are formed because:

A light will only travel a certain distance before it stops.

B a substance called ‘darkness’ collects behind some objects.

C some objects do not give out light in all directions.

D light cannot go through some objects.

Light

Swap your books to mark each other’s answers.

Checkpoint

4 Which statement is true?

A Sound travels faster than light.

B Sound will not travel. Only light can travel.

C Light travels faster than sound.

D Light and sound travel at the same speed.

Light

Swap your books to mark each other’s answers.

Checkpoint

5 Objects that light can easily pass through are said to be:

A transparent.

B apparent.

C opaque.

D oblong.

Light

Swap your books to mark each other’s answers.

Checkpoint

6 Which phrase best completes the following sentence? We see things because:

A they are luminous.

B the Sun shines on them.

C light from them enters our eyes.

D light from our eyes shines on them.

Light

Swap your books to mark each other’s answers.

Checkpoint

7 Opaque objects can:

A transmit and reflect light.

B transmit and absorb light.

C reflect and absorb light.

D only reflect light.

Light

Swap your books to mark each other’s answers.

Checkpoint

8 Which of these will absorb the most light?

A a white sheet of paper

B a sheet of clear glass

C a black piece of card

D an orange piece of card

Light

Swap your books to mark each other’s answers.

Checkpoint

9. Which of these diagrams show how light rays travel?... There may be more than one that is right!

I still feel unsure. I need some more help to understand.

I feel ok. I need to do some more work to check my understanding.

I am happy and feel I understand and can explain the main points.

(L4) Describe how light travels from luminous sources.

(L5) Explain how we see both luminous and non-luminous light sources.

(L6) Use ray diagrams to show how we see both luminous and non-luminous objects.

Light

Are you now able to…

Checkpoint

AMBULANCE

​

WE

​

ARE

​

LEARNING

​

ABOUT

​

REFLECTION

P4 Waves

Try and draw mirror images of the words:

Do Now

P4 Waves

Can you decipher the hidden message?

Do Now

P4 Waves

How could you explain why this is happening?

Starter

P4 Waves

What types of reflection is there?

4.2.1.1 Describe the formation of an optical image by a plane mirror and give its characteristics

Mirror

Specular

Diffuse

1.

2.

3.

4.

5.

6.

P4 Waves

What objects reflect light well?

4.2.1.2 2 Recall and use the law angle of incidence i = angle of reflection recognising these angles are measured to the normal

The Law of Reflection =  the angle of reflection is equal to the angle of incidence

P4 Waves

Reflection Experiment

Task 2

You will need:

• Ray box
• Slit
• Paper
• Protractor
• Ruler
• Mirror
• Pencil

Method

1. Draw a mirror line on paper
2. Add a normal line at 90° to the mirror
3. Put the mirror on the paper and shine the ray at it.
4. Use a pencil to mark the incident and reflected rays.
5. Measure the angles between the incident and reflected rays.

Created by H Rogerson

normal

Incident ray

Reflected ray

P4 Waves

What is the method?

4.2.1.3 Perform simple constructions, measurements and calculations for reflection by plane mirrors

Conclusion

• Use the following words and write your own conclusion to the experiment:

​

• Angle, incidence, reflected, ray, normal, same

Created by H Rogerson

Conclusion

P4 Waves

4.2.1.3 Perform simple constructions, measurements and calculations for reflection by plane mirrors

reflection, changing, normal, measuring, angle, perpendicular, light

​

I will find out what the relationship is between the _________ of incidence and the angle of _________________. I will do this by shining a ray of ___________ onto the mirror. I will then measure the angles on each side of the ______________ line using a protractor. The normal line is _________________ to the mirror. I will repeat the experiment by _____________ the size of the angle of incidence and ________________ the angle of reflection.

Conclusion Support

P4 Waves

4.2.1.3 Perform simple constructions, measurements and calculations for reflection by plane mirrors

Answer the following questions in your books

Just write the answers

P4 Waves

4.2.1.3 Perform simple constructions, measurements and calculations for reflection by plane mirrors

P4 Waves

True or False.

Checkpoint

P4 Waves

How can we use reflection in the real world?

Extra Information

The two plane mirrors must be positioned at 45° from the vertical. Light is reflected at right angles from the top mirror onto the bottom mirror and into the eye of the viewer.

How does a periscope use reflection?

Reflection

How can we use reflection in the real world?

Task 3

Reflection can be very useful.

High-visibility strips are very reflective and make sure that this cyclist gets noticed when there is little light.

Reflection

Captain Khan’s Tropical Treasure Hunt

Task 4

How to draw a ray diagram: watch

Ahoy there me harties! I have buried a hoard o’ treasure somewhere on this tropical island. Use this map and the laws of reflection to find the path.

Only those who listened to their science teacher will be loaded with gold (that’ll teach ya!) The landlubber who comes the closest shall receive the booty.

A word of warning to ya, only fools will climb the doom...

Reflection

A teacher has a small torch. He switches it on and points it towards a mirror.

Exam Question

Exam question:

​

A ray of light from the torch reflects off the mirror. Use a ruler and protractor to draw the ray of light:

(i) from the torch to the mirror;

1 mark

(ii) reflecting off the mirror.

2 marks

Rest position

Amplitude – the height of the wave. Measure from rest position to crest or trough

​

Wavelength – the distance from one crest to the next crest (or trough to next trough)

1

2

3

4

P4 Waves

What are the parts of a wave?

4.1.3 State the meaning of speed, frequency, wavelength and amplitude

P4 Waves

Period and Frequency

4.1.3 State the meaning of speed, frequency, wavelength and amplitude

P4 Waves

Calculating the speed of sound waves

4.4.6 Recall and use the equation v = f λ

P4 Waves

Write the correct name for each number

Do Now

1.

2.

3.

4.

5.

6.

P4 Waves

True or False

Do Now

1. The wavelength of light determines its colour.
2. A glass prism can split white light into its component colours because of the refraction of light.
3. Dispersion occurs when light passes through a medium and bends, causing the different wavelengths of light to spread out.
4. Shorter wavelengths of light appear as red colours in the visible spectrum.
5. Dispersion of light is more pronounced when light passes through a denser medium like water compared to air.

1

​

​

​

​

2

​

​

​

​

3

1. Transparent

​

​

​

• Translucent

​

​

​

• Opaque

Match 1 2 3 and A, B, C together!

Transparent – these are materials which let all of the light straight through.

Translucent – these materials let light through but it is randomly scattered.

Opaque – these materials let no light through.

P4 Waves

What is happening in each of the photos?

Starter

P4 Wave

4.2.2.1 Interpret and describe an experimental demonstration of the refraction of light

http://micro.magnet.fsu.edu/primer/java/scienceopticsu/refraction/index.html

​

http://www.bbc.co.uk/learningzone/clips/refraction/13525.html

​

1. Draw a line around the glass block;

​

• Draw a normal line, on one side of the glass, which is at a right angle to the surface of the block;

​

• Use a ray box to shine a ray of light into the glass block, entering it at the normal line;

​

• Mark the path of the ray of light through the block with two crosses;

​

• Mark the position of the light leaving the glass block with two crosses,

​

• Remove the glass block and draw a normal line at the point where the light exits;

​

7 Plot the path of the ray of light.

Investigating Refraction

P4 Wave

4.2.2.1 Interpret and describe an experimental demonstration of the refraction of light

In pairs you need to collect

​

Everything shown in this diagram plus a protractor!

P4 Wave

4.2.2.1 Interpret and describe an experimental demonstration of the refraction of light

I noticed that the ray of light is refracted (away from/towards) the normal when it goes into a glass block.

​

​

The ray of light is refracted (away from/towards) the normal when it comes out of a glass block.

​

​

The angle of incidence is (smaller than/equal to/larger than) the angle of emergence.

​

​

The angle of refraction is (smaller than/equal to/larger than) the angle of incidence.

P4 Wave

Conclusion

4.2.2.1 Interpret and describe an experimental demonstration of the refraction of light

WHY did the light bend both as it went into the glass block and as it left the glass block?

​

Talk to the person next to you about this for 1 minute.

Why was the light refracted?

P4 Wave

4.2.2.1 Interpret and describe an experimental demonstration of the refraction of light

This is because glass is more dense than the air and it slows down the light.

Why was the light refracted?

P4 Wave

4.2.2.1 Interpret and describe an experimental demonstration of the refraction of light

Why was the light refracted?

P4 Wave

4.2.2.1 Interpret and describe an experimental demonstration of the refraction of light

Can you now explain what is happening in each of these photos?

P4 Wave

4.2.2.1 Interpret and describe an experimental demonstration of the refraction of light

This diagram shows what happens to light which is reflected by the pencil.

​

The light bends when it leaves the water.

​

Your brain thinks that light always travels in straight lines so the pencil tip seems to be nearer the surface than it really is.

​

​

Can you now explain what is happening in each of these photos?

P4 Wave

4.2.2.1 Interpret and describe an experimental demonstration of the refraction of light

P4 Wave

Where is the fish actually?

4.2.2.1 Interpret and describe an experimental demonstration of the refraction of light

• Because of this bending, a fish in water looks nearer to the surface than it really is.

​

• Aborigine hunters have trained themselves to correct for this when fishing so that they catch their tea successfully.

Can you help Mr Trent catch the fish?

P4 Wave

4.2.2.1 Interpret and describe an experimental demonstration of the refraction of light

1. Refraction is what happens when light:

​

A hits an opaque object.

B bounces off a mirror.

C is scattered by a rough surface.

D bends as it goes from one substance into another.

Refraction

Quiz – Write your answers in your book

Plenary

2. Refraction occurs because

​

A light speeds up when it meets a denser transparent material.

B light slows down when it meets a denser transparent material.

C light stops when it meets a denser transparent material.

D light reflects inside denser transparent materials.

Refraction

Quiz – Write your answers in your book

Plenary

3 Which diagram shows the correct rays?

Refraction

Quiz – Write your answers in your book

Plenary

4. Where does refraction take place?

​

A in the centre of a transparent substance

B all the way through a transparent substance

C as light travels from one opaque substance into another

D as light travels from one transparent substance into another

Refraction

Quiz – Write your answers in your book

Plenary

1. Refraction is what happens when light:

​

A hits an opaque object.

B bounces off a mirror.

C is scattered by a rough surface.

D bends as it goes from one substance into another.

Refraction

Swap books – check your answers

Plenary

2. Refraction occurs because:

​

A light speeds up when it meets a denser transparent material.

B light slows down when it meets a denser transparent material.

C light stops when it meets a denser transparent material.

D light reflects inside denser transparent materials.

Refraction

Swap books – check your answers

Plenary

3. Which diagram shows the correct rays?

​

Refraction

Swap books – check your answers

Plenary

4. Where does refraction take place?

​

A in the centre of a transparent substance

B all the way through a transparent substance

C as light travels from one opaque substance into another

D as light travels from one transparent substance into another

Refraction

Swap books – check your answers

Plenary

Refraction

Are you now able to…

Learning Objectives

I still feel unsure. I need some more help to understand.

I feel ok. I need to do some more work to check my understanding.

I am happy and feel I understand and can explain the main points.

(L3) Can state what happens to light as it hits glass at an angle.

(L4) Can describe how light bends towards or away from the normal when it changes medium.

(L5) Explain why refraction happens.

Air

Air

Glass

Angle of Incidence

i

r

e

Angle of Refraction

Angle of Emergence

As light enters, it slows and bends toward the normal

This is because glass is more dense than the air and it slows down the light.

Dispersion

Why was the light refracted?

Do Now

Dispersion

Explain how the trick works

Starter

The water refracts the light rays coming from the coin.

P4 Waves

What would life be like without colour?

Extra Information

Dispersion

Dull.

Dispersion

Challenge: Can you make a rainbow using glass prism and white light?

Task 1

Dispersion

Breaking up white light

You’ve just seen how a prism can break up white light into 7 colours.

This breaking up of white light is called dispersion. The prism disperses the light.

Dispersion

This breaking up of white light is called dispersion. The prism disperses the light.

RED

ORANGE

YELLOW

GREEN

BLUE

INDIGO

VIOLET

When white light is broken up like this the 7 colours are always in the same order.

Dispersion

Can you remember all 7?

ROY GBIV

A spectrum is a range of different waves

Dispersion

Can you remember all 7?

Research and create a 1 page information booklet about electromagnetic radiation.

1 Describe the main features of the electromagnetic spectrum.

2 Explain the movement of electromagnetic waves, and the speed of light in a vacuum.

3 Describe the role of electromagnetic waves in:

• radio and television communications (radio waves),

• satellite television and telephones (microwaves),

• electrical appliances, remote controllers for televisions and intruder alarms (infra-red),

• medicine and security (X-rays).

4 Explain safety issues regarding the use of microwaves and X-rays.

(L3) Recall that white light can be split to make a spectrum.

(L4/5) Describe and attempt to explain some effects of dispersion.

(L5) Explain why we classify some

colours as primary and secondary colours.

Why does light disperse like this?

The size of a wave is measured from one peak to the next and is called its wavelength.

(L3) Recall that white light can be split to make a spectrum.

(L4/5) Describe and attempt to explain some effects of dispersion.

(L5) Explain why we classify some

colours as primary and secondary colours.

White light is made up of all the colours of the rainbow.

Each colour has its own wavelength.

​

Red has the longest and violet has the shortest wavelength.

(L3) Recall that white light can be split to make a spectrum.

(L4/5) Describe and attempt to explain some effects of dispersion.

(L5) Explain why we classify some

colours as primary and secondary colours.

But the shorter wavelengths slow down most and so bend more sharply.

When light enters a glass prism it slows down.

​

​

​

​

​

Blue is a short wavelength.

​

Red is the longest one.

(L3) Recall that white light can be split to make a spectrum.

(L4/5) Describe and attempt to explain some effects of dispersion.

(L5) Explain why we classify some

colours as primary and secondary colours.

As each wavelength, or colour, slows down at a different rate it therefore has a different angle of refraction to the rest.

​

This means the

different colours

spread out.

Blue Bends Best

When a second prism is added ‘upside down’ the dispersion of the second prism is in the opposite direction to the original dispersion.

White light is formed again.

Dispersion

Can you recombine colours?

Dispersion

Can you remember all 7?

ROY GBIV

Write 1-7 in your books

Write down the colour light (s) that will pass through the filter.

Dispersion

ROY GBIV

Dispersion

Dispersion

Light vs Art

There are three primary colours of light used to make all other colours. What are these colours?

red

green

blue

The three primary colours of light are red, green and blue.

magenta

Dispersion

Colours are made by mixing other colours of light.

A red filter absorbs all colours…

A blue filter absorbs all colours…

A green filter absorbs all colours...

…apart from red light.

…apart from blue light.

…apart from green light.

A magenta filter absorbs all colours…

A cyan filter absorbs all colours…

A yellow filter absorbs all colours...

…apart from red and blue.

…apart from green and blue.

…apart from red and green.

A magenta filter absorbs all colours…

A cyan filter absorbs all colours…

A yellow filter absorbs all colours...

…apart from red and blue.

…apart from green and blue.

…apart from red and green.

Filters let certain colours of light pass through, but absorb all other colours.

1

Filters let certain colours of light pass through, but absorb all other colours.

2

Filters let certain colours of light pass through, but absorb all other colours.

3

Filters let certain colours of light pass through, but absorb all other colours.

4

Filters let certain colours of light pass through, but absorb all other colours.

4

Filters let certain colours of light pass through, but absorb all other colours.

5

Filters let certain colours of light pass through, but absorb all other colours.

6

Filters let certain colours of light pass through, but absorb all other colours.

7

Dispersion

Learning Objectives

(L3) Recall that white light can be split to make a spectrum.

(L4/5) Describe and attempt to explain some effects of dispersion.

(L5) Explain why we classify some

colours as primary and secondary colours.

I still feel unsure. I need some more help to understand.

I feel ok. I need to do some more work to check my understanding.

I am happy and feel I understand and can explain the main points.

1. The range of colours in a rainbow is known as a ___________.
2. A ___________ is formed when sunlight is dispersed off raindrops.
3. White light passing through a prism is __________ into different colours.
4. __________ light is dispersed the most by a glass prism.
5. __________ light is dispersed the least by a glass prism.
6. The bending of light is known as __________,
7. A piece of apparatus which absorbs some colours of light but allows particular colours through is called a __________.
8. When green light hits a blue filter, it is __________.
9. A full moon ____________ sunlight, particularly __________ coloured light.
10. A ________________ lens is thinner in the middle and fatter at both ends.

P4 Waves

How do we see light?

4.2.3.1 Describe the action of a thin converging lens on a beam of light

P4 Waves

4.2.3.2 Use the terms principal focus and focal length

Principle Focus

Focal length

Convex Lens

• A converging lens causes the rays to converge at a focal point behind the lens so that a sharper image can be seen or photographed.

P4 Waves

P4 Waves

P4 Waves

2f

f

• Real
• Same Size
• Inverted

​

P4 Waves

• Uses:
• Photocopier

Principle Focus

Focal length

Convex Lens

2f

f

• Real
• Diminished
• Inverted

​

• Uses:
• Camera
• Eye

​

P4 Waves

Principle Focus

Focal length

Convex Lens

2f

f

• Real
• Magnified
• Inverted

​

• Uses:
• Projector

​

P4 Waves

Principle Focus

Focal length

Convex Lens

• Virtual
• Magnified
• Upright

​

• Uses:
• Magnifying glass

​

P4 Waves

Create an A3 Summary Poster on Light

• Properties of Light (speed, energy)
• Reflection
• Refraction
• Colour
• Dispersion
• Filters and how they are used in 3D goggles

​

• Due: Wednesday 9^th February.

​

Electromagnetic Spectrum

What is the speed of light?

• All the EM waves can be arranged according to their frequency or wavelength. The result looks like this:

Electromagnetic Spectrum

What is the electromagnetic spectrum?

• Radio waves have long wavelengths and very low energy, so they are useful for transmitting information for radio and television.�
• Microwaves have a shorter wavelength and higher energy. They are used for satellite and telephone communications, as well as microwave ovens.�
• Electrical appliances like remote controllers and intruder alarms use infrared waves.

​

• X-Rays are used for medicine and in security scanners, since they can penetrate light materials like fabric and skin (higher energy).

Electromagnetic Spectrum

Uses of EM ways

• Because X-rays can penetrate your skin, there is a chance that they can harm the cells in your body.

​

• This is why you will typically be protected with a lead vest when you visit the doctor or dentist

Electromagnetic Spectrum

Safety – X-rays

• Since microwaves have much lower energy than X-rays, lead protection is not necessary.�
• They typically do not have enough energy to penetrate the skin, but extended exposure is not recommended.

Electromagnetic Spectrum

Safety Microwaves

• Ultraviolet radiation has much more energy than microwave, and can damage skin cells with sufficient exposure. �
• Wearing sunscreen, hats, and long clothing can prevent this, and polarized sunglasses to protect your eyes are recommended.

​

• NOTE: UV radiation does not get absorbed by clouds, so you can still get burnt on a cloudy day!

Electromagnetic Spectrum

Safety - UV

1.

2.

3.

4.

5.

6.

P4 Waves

What objects reflect light well?

4.2.1.2 2 Recall and use the law angle of incidence i = angle of reflection recognising these angles are measured to the normal

The Law of Reflection =  the angle of reflection is equal to the angle of incidence

Rest position

Amplitude – the height of the wave. Measure from rest position to crest or trough

​

Wavelength – the distance from one crest to the next crest (or trough to next trough)

1

2

3

4

P4 Waves

What are the parts of a wave?

4.1.3 State the meaning of speed, frequency, wavelength and amplitude

Dispersion

Breaking up white light

You’ve just seen how a prism can break up white light into 7 colours.

This breaking up of white light is called dispersion. The prism disperses the light.

Air

Air

Glass

Angle of Incidence

i

r

e

Angle of Refraction

Angle of Emergence

As light enters, it slows and bends toward the normal

Dispersion

Light vs Art

Dispersion

Can you remember all 7?

ROY GBIV

A spectrum is a range of different waves