Wave Motion

How do waves transfer energy?

Longitudinal & Transverse Waves

LEARNING OUTCOMESA student is able to :• Describe what is meant by wave

motion.• Recognise that waves transfer energy

without transferring matter.Recognise that waves transfer energywithout transferring matter.

• Compare transverse and longitudinalwaves and give examples of each.

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INTRODUCTION• We always think of waves as sea waves.

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There are many kinds of waves .

All waves transmit energy.

These waves include waves we cannot seesuch as the sound waves created when wespeak.

The study of waves is important in our daily The study of waves is important in our dailylife. The music we hear, the colours of therainbow that we see and even the X-ray usedin hospitals are examples of waves that areery helpful to mankind.

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A stone is dropped into the water. What doyou see?

• Waves that move outward from the center

• The energy of the stone is converted towaves

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• Energy transfer through sea wavesmotion can be huge.

• For example during tsunami, the energycarried by water waves from the sea cancarried by water waves from the sea cancause great damage to thesurroundings. Most of the energycomes from the winds blowing acrossthe surface of the sea.

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TsunamiEffect

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What is waves?

Waves is a process of transferring

energy from one location to

another which is produced by ananother which is produced by anoscillating or vibrating motion

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Vibrating system : produces waves

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Oscillating system produces waves

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HOW DO WAVESTRANSFER ENERGY?TRANSFER ENERGY?

How do waves transfer energy?

• When a stone is dropped into a pond,water waves is produced.

• The direction of propagation of thewater waves is from ______ to ____.left rightwater waves is from ______ to ____.

• The cork represents the ______particles.

•

left right

water

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• The cork does not move together with thewave, instead it moves _____ and _________about its initial position.

• Waves transfer ________ as they move alongthe water particles. However, the waves donot carry the _______ particles along with

up down

energy

waternot carry the _______ particles along withthem.

water

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How do waves transfer energy?

• This shows that wave transferringenergy without transferring matter.

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TYPES OF WAVES

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2 types of waves

1. Transverse waves

2. Longitudinal waves

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Transverse Waves

• A transverse wave is a wave in which thevibration of particles in the medium is____________ to the direction ofpropagation of the wave.

• Example: _____________,_____

perpendicular

Water wave, light wave• Example: _____________,_____Water wave, light wave

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Longitudinal Waves

• A longitudinal wave is a wave which thevibration of particles in the medium is______________ the direction of propagationof the wave.

Parallel to

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• The slinky spring moves backwards andforwards to produce a longitudinal wave.

• The particles of the medium (spring) move___________ to the direction of the wave.The wave that travels along the springconsists of a series of ___________ and

parallel

Compressionconsists of a series of ___________ and____________.

Compressionrarefaction

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Activity 1: To observe a longitudinal waveand a transverse wave using a slinky spring.

• Hold one end of a slinky spring and give asharp push at the other end of the springbackward and forward. Observe themovement of the spring.

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– Sketch the longitudinal wave produce bythe slinky spring.

– Label the parts of compression and rarefactionof the spring and the wavelength of the waveproduced.

– Show the direction of the vibration of thecoloured thread and the direction of propagationof the wave (movement of the spring.MOZAC

– The coloured thread whichrepresents a particle of the mediumvibrate _________ to the propagationof the wave.

– The wave that travels along thespring consists of a series of

parallel

spring consists of a series of____________ and ____________

– The _____________ is the distancebetween two successive rare fractionor two successive compression

compression Rare factionwavelength

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2. Use the same slinky spring move the otherend of the spring side ways. Observe themovement of the spring.

• Sketch the transverse wave produced by theslinky spring.

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• Label the wavelength of the wave produced.

• Show the direction of the vibration of thecoloured thread and the direction ofpropagation of the wave (movement of thepropagation of the wave (movement of thespring.

• The vibration of the coloured thread is_________ to the direction of thepropagation of the wave.perpendicular

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Conclusion

• A longitudinal wave is a wave in which thevibration of the medium is_______________to the direction of thepropagation of wave.

parallelpropagation of wave.

• A transverse wave is produced when thevibration of the medium is________________ to the direction of thepropagation of wave.

perpendicular

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Quiz 1

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Quiz 2

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Summary 1• Waves are produced by vibrating systems• Waves transfer energy. Waves that travel

through a medium transfer energy withouttransferring matter.

• In transverse waves, the direction of wavepropagation is perpendicular to the direction ofvibration of the particles. Example: water wavesvibration of the particles. Example: water waves

• In longitudinal waves, the direction of wavepropagation is parallel to the direction ofvibration of the particles. Longitudinal wavesneed a medium to propagate. This type of wavescannot propagate through a vacuum. Example : asound wave

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