Physics Lesson 4a — Waves

Wave Anatomy

Spec 3.3

🌊📏🔺🔻〰️

Learning Objectives:

3.3 – Know the definitions of amplitude, wavelength, wavefront, crest, trough and rest position.
3.1 – Use the units: metre (m).

🏆 By the end I will be able to…

All: name the parts of a wave and label a wave diagram.

Most: define amplitude, wavelength, crest and trough with correct units.

Some: explain what a wavefront is and distinguish it from wavelength.

Navigation: Arrow Keys or Spacebar

🖨️ Paper Packs (backup — today is screen-first!)

⏱️ 40-Minute Pacing Guide

Core path (40 min): Arrival → Starter → I Do → We Do → Independent → Exit Ticket

FLEX slide (Observe): Use if time allows, or as next-lesson warm-up. Marked with 🟠 FLEX badge. This is part 1 of 3 — followed by 4b Frequency & Period and 4c Energy Transfer.

⏱️ 4 min

Arrival Task

Arrival Task – What Do You Already Know?

Instructions: Tap your answer on the board or your device — green = correct, keep trying if it shakes! New topic, so best guesses welcome.

1. 🟢

Which of these is an example of a wave?

A) A bookB) Sound from a speakerC) A chairD) A pencil

✅ B) Sound from a speaker.

2. 🟢

If you drop a stone into a pond, what happens to the water?

A) It disappearsB) Ripples spread outwardC) It turns to iceD) Nothing happens

✅ B) Ripples (waves) spread outward in circles from where the stone entered.

3. 🟢

Does a duck on a pond move across the water when a wave passes?

A) Yes, it travels with the waveB) No, it just bobs up and downC) It sinksD) It speeds up

✅ B) No — it bobs up and down. The duck doesn't travel with the wave.

4. Lead-in 🌊

If you looked at a wave's shape, what would you call the very top of it?

A) The bottomB) The crest (top)C) The middleD) The width

✅ B) The crest — the highest point of a wave.

1. 🟠

Which of these is NOT usually described as a wave?

A) SoundB) WaterC) A brickD) Light

✅ C) A brick. Sound, water and light all travel as waves.

2. 🟠

What do you think "amplitude" might mean, just from the sound of the word?

A) How loud/tall something isB) How fast it movesC) A type of fishD) A colour

✅ A) "Ample" means large — amplitude is about how tall/big the wave is.

3. 🟠

In a wave diagram, what do you think "wavelength" might measure?

A) The height of the waveB) The distance from one wave to the nextC) The speed of the waveD) The colour of the wave

✅ B) The distance from one point on a wave to the same point on the next wave.

4. Lead-in 🌊

If a wave has a "trough", what do you think this means?

A) The highest pointB) The lowest pointC) The middleD) The edge

✅ B) The lowest point of a wave.

1. 🔵

What is the crest of a wave?

A) The lowest pointB) The highest pointC) The middleD) The distance between waves

✅ B) The highest point. (The trough is the lowest point.)

2. 🔵

What do you think a "wavefront" might be?

A) A single point on a waveB) A line joining points at the same stage of a waveC) The front of a boatD) The end of a wave

✅ B) A line joining all the points on a wave at the same stage of vibration (e.g. all the crests).

3. 🔵

The "rest position" of a wave is…

A) Where the wave never movesB) The middle level the wave oscillates aroundC) The highest pointD) The lowest point

✅ B) The middle level the wave moves up and down around.

4. Lead-in 🌊

Amplitude and wavelength are both measured in the same unit. What is it?

A) SecondsB) HertzC) MetresD) Degrees

✅ C) Metres (m) — both are distances.

⏱️ 4 min

Starter

Starter: BE the Wave! 🌊🙌

Everyone becomes the wave — standing up, or arms-only from your seat. Arms UP = crest 🔺 · Crouch / arms DOWN = trough 🔻 · Arms flat = rest position ➖ · Big moves = big amplitude 💪. Watch the caller and react FAST!

Ready…

Press start when everyone is set

🗝️ The moves

🔺 CREST — arms stretched UP high

🔻 TROUGH — crouch / arms down low

➖ REST POSITION — arms out flat and level

💪 BIG amplitude — huge swings · 🤏 small amplitude — tiny wiggles

➡️ MEXICAN WAVE — ripple across the room in seat order!

Shout-out round (while you catch your breath): Where have you seen a real wave this week? Sea, puddle, speaker, heart monitor…

⏱️ 5 min

I Do

I Do: Wave Anatomy (3.3)

Key Idea: You must know 6 parts of a wave: crest, trough, rest position, amplitude, wavelength, wavefront.

0 / 6 revealed

📐 The 6 Key Definitions

Crest — the highest point of a wave.

Trough — the lowest point of a wave.

Rest position — the middle level a wave oscillates around when there's no disturbance.

Amplitude — the maximum displacement from the rest position. How "tall" the wave is. Measured in metres (m).

Wavelength (λ) — the distance from one point on a wave to the same point on the next wave (e.g. crest to crest). Measured in metres (m).

Wavefront — an imaginary line joining all the points on a wave that are at the same stage of vibration (e.g. all the crests).

🎛️ Live Wave Machine — come up and drive it!

💪 Amplitude (how TALL) ↔️ Wavelength (how SPREAD OUT) ⚡ Speed

Show labels

🌍 Why This Matters

Surfers read wave height (amplitude) and spacing (wavelength) to catch the perfect wave. Engineers measure amplitude to predict flood risk from waves. Every wave — water, sound, or light — has the same basic anatomy.

💡 Memory tricks:
Amplitude = how Amazing (tall) the wave is
λ (lambda) = Length of one wave
Crest is at the top, like the crest of a hill

🔑 Keywords to Know

Crest / Trough	Highest / lowest point of a wave.
Amplitude	How TALL the wave is — maximum displacement from rest. Metres (m).
Wavelength (λ)	Distance from one crest to the next. Metres (m).
Wavefront	Line joining points at the same stage of vibration.

Talk to your partner: Point to the diagram and take turns naming each of the 6 parts in your own words. Be ready to label the wave yourself next.

⏱️ 5 min

We Do

We Do: Label the Wave 🏷️

Instructions: Select a label, then click the correct slot. Match all 7!

👥 Think-Pair-Share: Try it yourself → discuss with your partner → agree on the answer.

Crest Trough Amplitude Wavelength Rest position Wavefront Metres (m)

Parts of a Wave

The highest point is called the ?

The lowest point is called the ?

The height from rest to crest is the ?

The distance from one crest to the next is the ?

The flat line the wave oscillates around is the ?

More Vocabulary

A line joining points at the same stage of vibration is the ?

Wavelength and amplitude are both measured in ?

Matched: 0 / 7

⏱️ 4 min · FLEX

📺 Observe

Observe: See Wave Anatomy in Action

Watch & check: You've met all 6 wave parts — now see real water waves in a ripple tank. Watch the clip, spot the things below, then finish the sentences.

Open on YouTube ↗ Backup clips ↗

If the video is blocked on the network, use the links above — or revisit the wave diagram on the I Do slide.

👀 While you watch, spot:

The crests and troughs as the waves ripple out
How the wavelength is measured — crest to crest
The rest position the water returns to between waves

Listen carefully: the exam-safe word for "how tall" is always amplitude, not "wavelength" — they're easy to mix up.

🗣️ Say the missing words OUT LOUD with your partner — no writing:

The wavelength is measured from one ____________ to the next.
The amplitude is measured from the ____________ position to the crest.

The highest point of a wave is the ____________.
The lowest point of a wave is the ____________.

Wavelength: crest to the next crest. Amplitude: rest position to the crest. Highest point: crest. Lowest point: trough.

Ready check: Cover the screen — can you say all 6 wave parts out loud, in order? If yes, you're ready for independent work.

⏱️ 8 min

Independent Work

Independent Work: Wave Challenge Zone 🎮

Instructions: Two challenges, all on screen — no worksheets! Work on your device, or take turns driving the board. Type your name at the bottom and print your evidence when done.

🌊 Challenge 1: Wave Builder

1️⃣ Make a wave with a BIG amplitude — push the amplitude above 70.

💪 Amplitude ↔️ Wavelength

⚡ Challenge 2: Rapid Quiz — tap your answers

Exam tip: "how tall" = amplitude · "how spread out" = wavelength. Don't mix them up!

✅ Tap to tick — Success checklist

✓I can define crest, trough and rest position

✓I can define amplitude and wavelength, with units

✓I completed the Wave Builder challenges

✓I can explain what a wavefront is (Middle/Higher)

Paper backup:

🚀 Aspire: Finished? Set the Wave Builder to the biggest amplitude AND shortest wavelength — what kind of real sea would that be? Would you sail in it?

⏱️ 3 min

Exit Ticket

Exit Ticket – Check Your Learning

Instructions: Tap your answers on screen — no notes, no books, no conferring. Then tap a traffic light to show how you feel.

🟢 I'm confident — tap me

🟡 Getting there — tap me

🔴 I'm stuck — tap me

🖨️ Paper backup exit ticket:

🌊 Next lesson: Frequency & Period — how many waves pass per second, and how that links to the time each wave takes.

Name: ________________________ Class: __________ Date: ____________

🏆 Success Criteria — tick at the END of the lesson:

☐ I can define crest, trough and rest position.

☐ I can define amplitude and wavelength, with units.

☐ I can label all 6 parts on a wave diagram.

Knowledge Organiser: Wave Anatomy (L4a)

How to use: Read this before starting. Refer back during independent work. Cover it up for the exit ticket — that tests what you actually remember!

Concept	Details
Crest	The highest point of a wave.
Trough	The lowest point of a wave.
Rest position	The middle level a wave oscillates around with no disturbance.
Amplitude	Maximum displacement from rest position. Measured in metres (m).
Wavelength (λ)	Distance from one point to same point on next wave (crest→crest). Metres (m).
Wavefront	Line joining points at the same stage of vibration.

🧠 Memory Tricks

Amplitude = how Amazing (tall) the wave is.

λ (lambda) looks like an upside-down V = the Valley between two crests = wavelength.

Crest is at the top, like the crest of a hill.

📋 Exam Technique — Every Mark Counts!

1 mark = State / Name / Label the part.

2 marks = Definition + correct unit.

3+ marks = Full explanation. Explain questions need "because".

Golden rule: Write something for every question. Even a label = 1 mark.

Arrival Task – Multiple Choice (circle a letter)

Foundation 🟢

1) Which of these is an example of a wave? A) A book B) Sound from a speaker C) A chair D) A pencil

2) If you drop a stone into a pond, what happens to the water? A) It disappears B) Ripples spread outward C) It turns to ice D) Nothing happens

3) Does a duck on a pond move across the water when a wave passes? A) Yes, it travels with the wave B) No, it just bobs up and down C) It sinks D) It speeds up

4) If you looked at a wave's shape, what would you call the very top of it? A) The bottom B) The crest (top) C) The middle D) The width

Middle 🟠

1) Which of these is NOT usually described as a wave? A) Sound B) Water C) A brick D) Light

2) What do you think "amplitude" might mean, just from the sound of the word? A) How loud/tall something is B) How fast it moves C) A type of fish D) A colour

3) In a wave diagram, what do you think "wavelength" might measure? A) The height of the wave B) The distance from one wave to the next C) The speed of the wave D) The colour of the wave

4) If a wave has a "trough", what do you think this means? A) The highest point B) The lowest point C) The middle D) The edge

Higher 🔵

1) What is the crest of a wave? A) The lowest point B) The highest point C) The middle D) The distance between waves

2) What do you think a "wavefront" might be? A) A single point on a wave B) A line joining points at the same stage of a wave C) The front of a boat D) The end of a wave

3) The "rest position" of a wave is… A) Where the wave never moves B) The middle level the wave oscillates around C) The highest point D) The lowest point

4) Amplitude and wavelength are both measured in the same unit. What is it? A) Seconds B) Hertz C) Metres D) Degrees

Starter: Spot the Wave Shape

1. List 3 places you've seen waves in real life.

2. Draw a simple picture of a wave — what shape is it?

3. Look at your drawn wave — what would you call the very top part? And the very bottom part?

We Do Worksheet

Part A: Label the Wave

Write the correct label next to each description.

1. Highest point: _________ 2. Lowest point: _________ 3. Height from rest to crest: _________ 4. Distance crest to crest: _________ 5. Flat line wave oscillates around: _________

Word bank: Crest · Trough · Amplitude · Wavelength · Rest position

Part B: More Vocabulary

6. A line joining points at the same stage of vibration is the: _________

7. Wavelength and amplitude are both measured in: _________

Scaffolding Sheet

Wave Anatomy

Term	Definition	Unit
Crest	Highest point	—
Trough	Lowest point	—
Rest position	Middle level wave oscillates around	—
Amplitude	Max displacement from rest	m
Wavelength (λ)	Distance: one point → same point on next wave	m
Wavefront	Line joining points at same vibration stage	—

Key Rule

Amplitude is measured from the rest position up to the crest — not crest to trough.

Wavelength is measured between two matching points — e.g. crest to crest.

Independent Work – Foundation (Grades U–1)

You've got this! Use your scaffolding sheet. Point to the diagram before you answer each question.

Section A: Multiple Choice

1. The highest point of a wave is called the… [ ] Trough [ ] Crest [ ] Amplitude

2. Amplitude is measured in… [ ] Metres [ ] Hertz [ ] Seconds

3. The lowest point of a wave is called the… [ ] Crest [ ] Trough [ ] Wavefront

4. The distance from one crest to the next is called the… [ ] Wavelength [ ] Amplitude [ ] Rest position

Section B: Short Answer

5. Label this wave: write "Crest", "Trough", "Amplitude", "Wavelength" and "Rest position" on the diagram.

[Wave diagram — draw your own and label it]

6. State what unit amplitude is measured in.

7. What is the "rest position" of a wave?

Section C: Long Answer (Grade 2 Challenge — scaffolded)

8. (4 marks) Complete the sentences about wave anatomy.

The highest point of a wave is called the _________________________ . [1 mark]

The lowest point of a wave is called the _________________________ . [1 mark]

Amplitude is measured from the _________________________ position to the _________________________ . [2 marks]

Section D: Exam-Style

9. (3 marks) Define the following wave properties:

(a) Amplitude [1 mark]

(b) Wavelength [1 mark]

Independent Work – Middle (Grades 1–2)

Push yourself! Use full sentences for explanations. Section D is your Grade 3 stretch — give it your best shot.

Section A: Multiple Choice & Recall

1. Which quantity has the unit metres? [ ] Amplitude [ ] Time [ ] Neither

2. The rest position is… [ ] The highest point [ ] The middle level [ ] The lowest point

3. Define wavelength.

4. What is a wavefront?

Section B: Application

5. Label the parts on this wave diagram:

[Wave diagram — draw your own and label crest, trough, amplitude, wavelength, rest position]

6. Explain, in your own words, the difference between amplitude and wavelength. [2 marks]

Section C: Long Answer

7. (4 marks) A student says "amplitude is the distance from the crest to the trough." Explain why this is wrong, and describe how amplitude should be measured. [4 marks]

Section D: Exam-Style (Grade 3 Stretch)

8. (5 marks) A student draws a wave diagram. Describe how they would correctly mark on: (a) the amplitude [2 marks] (b) the wavelength [2 marks] (c) the rest position [1 mark]

Independent Work – Higher (Grades 3–5)

Aim high! Full sentences for explanations. Section D includes a Grade 5 challenge — show the examiner you can reason, not just label.

Section A: Recall

1. Define wavelength and state its unit. [2 marks]

2. Distinguish between a wavefront and a wavelength. [2 marks]

3. Explain how amplitude is correctly measured. [2 marks]

Section B: Application

4. Sketch and fully label a wave diagram, including the rest position, amplitude and wavelength. [4 marks]

5. Two waves have the same wavelength but different amplitudes. Explain what this would look like on a diagram. [3 marks]

Section C: Long Answer

6. (5 marks) A pupil says amplitude is "the distance from crest to trough." Explain why this is not quite correct, and describe the correct method, using the rest position in your answer. [5 marks]

Section D: Exam-Style (Grade 5 Challenge)

7. (4 marks) Explain the difference between a wavefront and a wavelength, using a diagram description to support your answer. [4 marks]

Exit Ticket – Foundation (U–1)

Name: _________________________ Date: _____________

1) What is the amplitude of a wave?

2) What is the highest point of a wave called?

3) What is the lowest point of a wave called?

Exit Ticket – Middle (1–2)

1) Define wavelength.

2) What unit is amplitude measured in?

3) Explain what the "rest position" of a wave is.

Exit Ticket – Higher (3–5)

1) Distinguish between wavefront and wavelength.

2) A pupil says amplitude is "the distance from crest to trough." Explain why this is not quite correct.

3) Describe where you would draw the amplitude arrow and wavelength arrow on a wave diagram.

Wave Anatomy

🏆 By the end I will be able to…

🖨️ Paper Packs (backup — today is screen-first!)

⏱️ 40-Minute Pacing Guide

Arrival Task – What Do You Already Know?

1. 🟢

2. 🟢

3. 🟢

4. Lead-in 🌊

1. 🟠

2. 🟠

3. 🟠

4. Lead-in 🌊

1. 🔵

2. 🔵

3. 🔵

4. Lead-in 🌊

Starter: BE the Wave! 🌊🙌

🗝️ The moves

I Do: Wave Anatomy (3.3)

📐 The 6 Key Definitions

🎛️ Live Wave Machine — come up and drive it!

🌍 Why This Matters

🔑 Keywords to Know

We Do: Label the Wave 🏷️

Parts of a Wave

More Vocabulary

Observe: See Wave Anatomy in Action

Independent Work: Wave Challenge Zone 🎮

🌊 Challenge 1: Wave Builder

⚡ Challenge 2: Rapid Quiz — tap your answers

✅ Tap to tick — Success checklist

Exit Ticket – Check Your Learning

Knowledge Organiser: Wave Anatomy (L4a)

🧠 Memory Tricks

📋 Exam Technique — Every Mark Counts!

Arrival Task – Multiple Choice (circle a letter)

Foundation 🟢

Middle 🟠

Higher 🔵

Starter: Spot the Wave Shape

We Do Worksheet

Part A: Label the Wave

Part B: More Vocabulary

Scaffolding Sheet

Wave Anatomy

Key Rule

Independent Work – Foundation (Grades U–1)

Section A: Multiple Choice

Section B: Short Answer

Section C: Long Answer (Grade 2 Challenge — scaffolded)

Section D: Exam-Style

Independent Work – Middle (Grades 1–2)

Section A: Multiple Choice & Recall

Section B: Application

Section C: Long Answer

Section D: Exam-Style (Grade 3 Stretch)

Independent Work – Higher (Grades 3–5)

Section A: Recall

Section B: Application

Section C: Long Answer

Section D: Exam-Style (Grade 5 Challenge)

Exit Ticket – Foundation (U–1)

Exit Ticket – Middle (1–2)

Exit Ticket – Higher (3–5)

Pupil / Class Evidence

🎓 TA Focus

🎯 Cold Call

📺 Waves in a Ripple Tank

🏆 Class Progress Board

🎉 Lesson Complete!