Wave properties Book page Syllabus cgrahamphysics.com 2016

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1 Wave properties Book page Syllabus

2 Starter Challenge: There are 5 main oceans in the world. Can you name and locate them? Atlantic Arctic Ocean Ocean Indian Ocean Pacific Ocean Southern Ocean Extension: What do all oceans and seas have? Hint

3 Can you name the waterbodies that are not an ocean? Dead Sea Lake Erie Lake Victoria Lake Erie Dead Sea Mediterranean Sea Mediterranean Sea Lake Victoria

4 Can you match the wave pattern? Seismic wave Human voice Music beat Heart beat

5 What are waves and what do they do? Aim Key words Describe how waves move. Explain the basic properties of waves. Compare transverse and longitudinal waves. Displacement ( 배의 ) 배수량 Amplitude (a) ( 파동의 ) 진폭 Frequency 빈도 Wavelength (λ) 물결깊이 Longitudinal 경도 ( 경선 ) 의 Transverse 가로지르는, 횡행 Compression Rarefaction Particles Vibration Wave front

6 Have you ever wondered The big picture What does a wave transfer?

7 The two groups are: Mechanical waves and electromagnetic waves (EM) Did you know, there are 2 groups of waves with 2 different types of waves?! Mechanical waves have two subgroups: Transverse and Longitudinal Waves.

8 EM Waves 7 types Constructive- Low energy, minimum disturbance to the reef Real Men in violet underwear (are) extremely gorgeous Radio, Micro, infra red, visible, ultra violet, x-ray, gamma ray

9 Transverse waves

10 Copy this diagram into your books Amplitude Wavelength λ Trough Crest Node

11 LO: Understand the similarities and differences between types of waves Practical: Modelling waves The wave travels away from the source. The direction of the wave is at right angles to the movement of the source. In a transverse wave, the coils do not travel horizontally, each coil of the Slinky just vibrates up and down. source moves up and down coils vibrate up and down direction of wave Direction of energy cgrahamphysics.com transfer 2016

12 Definitions Amplitude (A): displacement from rest position Wavelength (λ): the distance between a particular point on a wave and the same point on the next wave Frequency (f): the number of waves passing a particular point number of waves per second, measured in Hertz (Hz) f = time Period (T): the time taken for the source to produce one wave Time and frequency are related by the equation frequency, f in Hertz = f = 1 T or T = 1 f 1 time period T,(in seconds)

13 What is the frequency? Waves: Frequency Wave Cycles Time (s) Freq (Hz)

14 Longitudinal Wave Constructive- Low energy, minimum disturbance to the reef

15 Longitudinal Wave λ Direction of energy transfer

16 LO: Understand the similarities and differences between types of waves Practical: Modelling waves The wave travels away from the source. The direction of the wave is parallel to the movement of the source. In a longitudinal wave, the coils do not travel horizontally, each coil of the Slinky just vibrates left and right. source moves left and right coils vibrate left and right direction of wave

17 Representation of sound waves Remember: Direction of energy transfer is parallel to wave motion Particles on wave move back and forth

18 Comparison longitudinal Sound Waves transverse Remember: Direction of energy transfer in a longitudinal wave is parallel to wave motion Particles on wave move back and forth A pressure wave can be transformed to be displayed as a transverse wave using cgrahamphysics.com an electrical 2016 signal in an oscilloscope

19 Oscilloscope Longitudinal pressure wave in Electrical signal wave out

20 Wave front λ A wave front is an imaginary line or surface that joined all adjacent points which have the same phase of vibration on the wave. Any two points on a wave are said to be in phase when they have completed identical fractions of their periodic motion.

21 The energy that a wave has depends on: -The frequency f -The speed v -The wavelength λ - The amplitude A Whiteboards: Waves are formed So, What why is when do the you link winds think between blow some waves across waves are the bigger and sea s the than surface. wind? others?

22 Plenary : What have you learnt about waves?

23 Transverse or longitudinal? Transverse light water s-waves Longitudinal sound p-waves ultrasound ultraviolet sound s-waves water light p-waves ultrasound ultraviolet

24 Which wave below is a longitudinal wave? A. Ultraviolet B. Water C. Light D. Sound

25 What are the units of frequency? A. Metres B. Hertz metres C. Hertz/metres D. Hertz

26 Mini-Plenary Match the term to the correct definition 1. Waves 2. Wavelength 3. Frequency 4. Amplitude a) The height of a wave above the zero line b) They transfer energy from one place to another c) The number of waves per second d) The distance from peak to peak/trough to trough on a wave

27 a Which two waves have the same amplitude? A B C D E

28 b Which wave has the highest frequency? A B C D E

29 c Which wave has the lowest frequency? A B C D E

30 d Which two waves have the same frequency? A B C D E

31 e Which wave has twice the amplitude of D? A B C D E

32 Key words Displacement distance from the rest position Amplitude (A) maximum displacement from rest position Frequency (f) number of waves per second Period (T) time it takes for the source to produce one wave Wavelength (λ) distance from one crest to the next or similar Longitudinal particles vibrate parallel to wave motion Transverse particles vibrate perpendicular to wave motion Compression areas of high pressure Rarefaction areas of low pressure Particles a point on a wave Vibration a rapid, repeated linear motion Wave front - an imaginary line that represents the distance between two crests