GENERAL PROPERTIES OF WAVESGCE ‘O’ LEVEL PHYSICS 5052

LESSON PLAN A: INTRODUCTION TO WAVES

Done by: Chew Yiming Clement (LG02) Supervisor: Mr Charles Chew

Module Code: QCP521

INTRODUCTION

The topic on General Wave Properties for 5052 Physics O Level is an important topic that sets the foundation for further study in topics on EM waves, Light and Sound. The topic will be taught in two lessons.

Lesson A: Introduction to Waves

Lesson B: The Wave Equation and its Applications

The lesson plan that follows is for Lesson A.

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LESSON PLANNING (LESSON A)

Topic: General Wave properties

Class: Secondary 3 Express (Average ability)

Content:(a) Describing wave motion

(b) Wave terms

(c) Longitudinal and transverse waves

Time: 2 periods (70 min)

Prerequisites and Prior Knowledge:

(a) Students should have learnt light and sound in Lower Secondary Science

(b) Students should have learnt the concept of speed and its definition.

(c) Students should have experience with water waves and have witnessed ocean waves.

Lesson objectives:

At the end of the lesson, students should be able to:

(a) Describe and explain what is meant by wave motion as illustrated by vibrations in ropes, springs and by waves in a ripple tank. (Waves in a ripple tank to be dealt in next lesson)

(b) Show understanding that waves transfer energy without transferring matter

(c) Define speed, frequency, wavelength, period and amplitude

(d) Compare transverse and longitudinal waves, and give suitable examples of each

(In lesson B)

(e) State what is meant by the term wavefront

(f) Recall the relationship velocity = frequency wavelength

(g) Apply the relationship between velocity, frequency and wavelength to new situations or to solve related problems.

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Learning Environment:

Classroom with whiteboard, OHT, a computer and a projector

Learning Aids & Resources:

(a) 1 × clear plastic basin (with wide base)

(b) 1 × rope

(c) 5 × slinky coil

(d) 1 × skipping rope

(e) Flash animations.

(f) 1 × newspaper article from Straits Times 15 Oct 2005 – ‘S’pore not safe from

tsunami’

(g) 2 × movie clips 1 × movie clip showing 26 Dec 2004 tsunami 1 × movie clip showing Tacoma Bridge collapse

(h) 11 × construction sheets (10 red, 1 yellow) for the wave game

(i) 1 × music clip

(j) PowerPoint Slides

(k) 1 × worksheets

(l) 1 × notes

(m)1 × dipper

Lesson Presentation:

Trigger Activity:(1) Take the clear basin and fill it with water. Place the basin onto the OHT. This is to

simulate a pond or a puddle of water. Now drop a coin gently into the basin and observe how the circular ripples move outwards to the surface of the water. This is similar to the effect caused by casting a pebble into a pond.

(2) Show applet of 26 Dec 2004 tsunami. This is to illustrate the destructive power of waves. Follow-up with newspaper cutting from the Straits Times 15 Oct 2005 – “‘S’pore not safe from tsunami’”.

Emphasise to the students that we encounter waves daily in our lives. There are also many application for waves in communications and medical science (radio sets, satellite

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technology, GPS, handphones, X-ray, photography). Tell the students that if they want to pursue these interests later in life, they must pay attention to the lesson, and learn more about waves!

Set Induction:The Wave GameAsk ten students to come to the front of the class. Make them stand in a straight line facing the class. Give them each a red construction paper. Tell them to do a continuous human wave. Synchronise the wave with some music. Using this activity, provide sufficient scaffolding to induce them to the properties of a transverse wave. For more details, refer to Procedure for Lesson Plan

Strategies for Lesson Development:

(a) Simple to complex. Concrete to abstract.One should not start off by introducing complex concepts before simpler concepts. The students will be confused. The lesson plan takes an inductive approach leading from specific to general examples, concrete to abstract concepts. Example: we begin by talking about waves in daily life before proceeding to classifying the waves into two different categories.

(b) Everyday ApplicationsThe continuous emphasis of the use of waves in everyday applications will make students more interested as they can relate them to their lives. Physics is useful and not just some theoretical exercise!

(c) Perceptual Learning StylesAccording to Dunn & Dunn (1978), students may have different perceptual learning styles. Learners may be auditory, visual or tactual/kinesthetic. Activities such as the wave game appeals to both kinesthetic and visual learners. Students will also get to play with the slinky coils. Those who learn better by writing down what they see and think have notes with blanks provided for them. They can fill in the blanks during the course of the lesson.

(d) Focusing on the EssentialsNo one can learn everything that is present in any textbook or lesson. Hence, it is important for the teacher to communicate what is most essential to the students. Notes with blanks are given out to fulfil the purposes. They contain the important definitions and concepts a student has to master from the lesson. The lesson closure also offers a recap using a concept map.

(e) Collaborative LearningTo integrate collaborative learning, students will be asked to take part in a Think-Share-Pair activity where they are required to brainstorm and list the application of waves in daily life.

Lesson Closure:The teacher will recap what the students have learnt using a concept map. The teacher will proceed to ask them some thinking questions that will prepare them for Lesson B on The

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Wave Equation and its Applications. Worksheets will also be given for students to do at home to facilitate their consolidation of concepts, as well as serve as student assessment.

Possible Learning Difficulties and Misconceptions:Most students find the topic of waves very abstract. Hence, there is a need for demonstrations so that students can visualise the concepts involved. Some misconceptions of waves include:

Waves transport matter.

There must be a medium for a wave to travel through.

Waves do not have energy.

All waves travel the same way.

Big waves travel faster than small waves in the same medium.

Concept Map:

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Reflection of lesson: The pace of the lesson was good. However, I can improve in the management of my

time during activities

The music clip hanged during the wave game. There is a need to prepare a contingency plan for teaching if technology fails.

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Procedure of Lesson Plan

Time Frame

Activities Resources Rationale

7 min Trigger ActivitiesActivity 1: Throwing a pebble into a pond (5min) Ask students if they had ever throne a

stone into a pond or a puddle of water. What happens when the stone hits the water?

Take a clear basin and fill it with water.

Place the basin onto the OHT. This is to simulate a pond

Using a dipper, create some circular ripples in the basin of water.

The teacher says, “This is what will happen when I throw a pebble into a pond. Do you see those circular ripples? Those are waves”

Remark: Distribute the notes before the trigger activity

Clear basin filled with water.

Dipper

To provoke students and prepare their mindset to explore more into the topic of waves.

To show that waves occur in everyday life.

Activity 2: Movie Clips(5min) Tell students that waves are not

always so harmless. They can be very destructive.

Show students movie clip of 26 Dec 2004 tsunami.

Follow this up by showing newspaper clip from Straits Times 15 Oct 2005 – ‘S’pore not safe from tsunami’

Show movie clip of Tacoma Bridge collapse.

Tell the students that waves occur in everyday life. Hence, it is important for us to study waves. There are also many applications for waves in the fields of medical science and communications. If they want to pursue their interests in these areas, they must know more about waves. Hence, they must pay attention in class.

Movie Clips

Newspaper Article

7 min Think-Pair-Share Distribute handout A.

Handout A To get students to think critically and

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Time Frame

Activities Resources Rationale

Ask them to work in pairs to fill in the 1st column the applications of waves in everyday life.

After they have finished, write some of the students’ answers on the whiteboard.

Ask them the reason for choosing some of the answers

Note: Some of the students’ answers might be wrong. It is fine at this time because the motive is to get them to think critically about what is a wave. They can learn from their mistakes

PowerPoint slides

construct their own understanding regarding the definition of a wave.

5 min Definition of a wave Take the clear basin of water and

placed it over the OHP. Create some ripples using the dipper again.

Bring to students’ attention the disturbance resulting from the vibrations caused by the ball falling into the water.

Show PowerPoint Slide explaining definition of waves.

Now that the students know the definition of waves, ask the students to evaluate their previous answers. Which are waves and which are not?

Emphasise that not all waves need a medium to propagate. Example: EM waves

Clear basin filled with water

Dipper

PowerPoint Slides

Introduce definition of wave using previous demonstrations and activities as scaffolding

8 min The Wave Game Ask ten students to come to the front

of the class and make them stand in a straight line facing the class.

Give each student a red construction paper

Ask the students to do a continuous human wave. If resources are sufficient, the human wave can be synchronised by a music clip.

Using a cardboard arrow, prompt the students to indicate the direction of propagation of the wave.

Using the other cardboard arrow, prompt the students to indicate the

10 red construction paper

2 cardboard arrows

Optional:Music clip

The intention of the wave game is to help students visualise the mechanics involved in a transverse wave.

Student-centered learning

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Time Frame

Activities Resources Rationale

direction each student is moving. Teacher to ask student what they

observe about the direction of the two arrows. (They are perpendicular to each other)

5 min Defining Transverse Waves Ask a student to hold one end of the

skipping rope while the teacher holds the other end.

The teacher moves his hand up and down to generate transverse waves.

Show the flash animation from http://www.bbc.co.uk/schools/gcsebitesize/flash/ph06008.swf. The flash animation shows an electronic representation of the rope wave.

Ask the students what are the similarities between the rope wave and the human wave in the wave game.

Show PowerPoint slide explaining what a transverse wave is.

Help students to remember for transverse waves, waves travel in a direction perpendicular to the direction of vibration using the symbol of a cross for the letter “t”.

Give some examples of transverse waves. Example: EM waves

Ask review question to test understanding of waves.

Skipping Rope

Flash Animation

PowerPoint Slides

Using activities to help student construct their understanding of what is a transverse wave.

Help students consolidate their understanding of transverse waves.

8 min Slinky Coil Demonstration Take a slinky coil and create

longitudinal waves. Pass the slinky coils for the student to

play along Show flash animation on longitudinal

waves. http://www.bbc.co.uk/schools/gcsebitesize/flash/ph06009.swf

Again using the two cardboard arrows, ask students to show the direction of propagation of the waves, and the direction of the vibration. Ask them how this is different from a transverse wave.

Show PowerPoint slides explaining the definition of a longitudinal wave.

Slinky Coil

Flash animation

2 Cardboard arrows

PowerPoint Slides

OptionalMovie Clip

Using activities to help student construct their understanding of what is a longitudinal wave.

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Time Frame

Activities Resources Rationale

For longitudinal waves, the direction of vibration is along the direction of the propagation of the waves.

Ask the students to observe that there are areas where the spring appears more compressed than other areas. Introduce concept of compressions and rarefactions.

Give examples of longitudinal waves in everyday life. Example: sound (if there is time, show video clip of candle flame flickering vigorously due to sound blasting from a loud speaker)

5 min Review Questions Ask students some simple question to

test whether they can compare and distinguish transverse and longitudinal waves.

PowerPoint Slides

Reinforce and assess students’ understanding of the concepts involved.

15 min Introducing crest, trough, amplitude and wavelength, frequency, period Get another 10 students to play the

wave game. This time give one of the students a yellow construction paper instead of a red construction paper. Synchronise the wave using some music.

Ask the students to freeze in their positions when you stop playing the music.

Stop the music when the student with the yellow construction paper is at his highest point. Introduce the idea of crests to the students.

Stop the music when the student with the yellow construction paper is at his lowest point. Introduce the idea of troughs to the students.

Using PowerPoint slides to introduce definitions of crest, trough, amplitude, wavelength, frequency and period to the students.

For relationship between frequency and period, ask the students to do handout 2 and observe the trend that frequency increases as period decrease. Ask why this occurs.

Construction Paper

Music Clip

PowerPoint Slides

Handout B

Optional:Flash Animation

Introducing wave terms to the students.

Visual representation allows students to understand abstract concepts better.

Get students discover implications of T=1/f via induction.

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Time Frame

Activities Resources Rationale

(If there is time, show flash animation on wave terms. Students can vary wave length, amplitude and frequency, and see the effect on the wave)

5 min Review Questions on wave terms Using PowerPoint, ask questions

regarding the wave terms to reinforce the students’ understanding of the wave terms.

(If there is time, introduce the concept of wave speed and a derivation of the wave equation. But it is not critical as it will be covered in the next lesson)

PowerPoint Slides

Reinforce students’ understanding of wave terms

5 min Lesson Closure Summarise the concepts taught using

the concept map. They are to fill up the blank spaces in their notes.

Pose the following questions to the students to think through before the next lesson Why don't incoming ocean waves

bring more water on to the shore until the beach is completely submerged?

In space films, we often hear the sound of the engine of the spaceship as the zoom past each other in outer space. We even hear the spaceship firing lasers at one another. What are your thoughts concerning this?

How will the motion of water waves change as they move from deep to shallow water? How about from shallow to deep water?

Notes Refresh the students’ memory concerning the concepts taught in the lesson.

Help the students focus on the essentials.

Thinking questions to set the students to inquire more into the subject

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References

1) Charles Chew, Leong See Cheng, Chow Siew Foong (2000). Physics A Course for ‘O’ Levels (2nd Edition), Federal, Singapore.

2) Rita Dunn, Kenneth Dunn (1978). Teaching Students Through Their Learning Styles – a practical approach, Prentice-Hall, Virginia, USA.

3) Loo Wan Yong, Loo Kwok Wai, See Toh Weng Fong (2000). Physics Insights, Pearson Education, Singapore.

4) Panagiotis Pantidos, Stamatis Patapis (2005). Kinesthetic Transverse Wave Demostration, The Physics Teacher, Vol. 43, p.344-345

5) http://www.physicsclassroom.com/Class/waves/U10L1c.html 6) http://www.bbc.co.uk/schools/gcsebitesize/physics/waves/

an_introduction_to_wavesrev1.shtml7) http://www.physicsclassroom.com/Class/waves/wavestoc.html 8) http://www.wfu.edu/physics/demolabs/demos/index.html 9) http://www.kettering.edu/~drussell/demos.html

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APPENDIX A

HANDOUT 1 FOR INTRODUCTION TO WAVES

Name: Class:

Examples and Applications of Waves in Everyday Life

Type of Waves (Transverse/Longitudinal)

Any medium involved?

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APPENDIX C

HANDOUT B FOR INTRODUCTION TO WAVES

Name: Class:

Exploring the relationship between period, T and frequency, f

We have just learnt that .

Let’s explore the implications of this relationship.

Frequency, f/Hz Period, T/s123456789

10 What do you observe?

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APPENDIX C

HANDOUT B FOR INTRODUCTION TO WAVES (ANSWERS)

Name: Class:

Exploring the relationship between period, T and frequency, f

We have just learnt that .Let’s explore the implications of this relationship.

Frequency, f/Hz Period, T/s1 12 0.53 0.3334 0.255 0.26 0.1677 0.1438 0.1259 0.111

10 0.1 What do you observe?

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APPENDIX E – NOTES WITH ANSWERS

UNIT 13 - GENERAL PROPERTIES OF WAVES

1. What is a wave?

It is a spreading of disturbance from one place to another.

The source of the wave is a vibration or an oscillation.

Energy is transferred from one point to another without physical transfer of any

material between two points.

2. Do waves need a medium to propagate? No

3. Transverse waves travel in a direction perpendicular to the direction of the vibrations.

Some examples of transverse waves: water waves, rope waves, EM waves

4. Longitudinal waves travel in a direction parallel to the direction of the vibrations.

5. Crests: Points of maximum displacement on a wave.

Troughs: Points of minimum displacement on a wave.

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distancealong rope

displacementCREST CREST

TROUGH

6. Amplitude (A): Maximum displacement from the rest or central position.

SI unit: metre (m)

7. Wavelength (): Distance between two successive points of the same phase.

Example: distance between two crests.

SI unit: metre (m)

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distance along rope

crest crest

trough

amplitude

amplitude

displacement

distance

crest crest

trough

λ

amplitude

amplitude

displacement

8. Frequency (f): Number of waves generated per second.

SI unit: hertz (Hz)

9. Period (T): Time taken to generate one complete wave (or to complete one cycle).

SI unit: seconds (s)

10. Relationship between period, T and frequency, f:

As f increases, T decreases.

CONCEPT MAP:

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APPENDIX F – NEWSPAPER CLIP AND POWERPOINT SLIDES

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