Objective Explore the features of a 26112020 wave
Objective: Explore the features of a 26/11/2020 wave OUTCOMES: Developing Progressing Advancing Excelling State what a wave is Describe the motion of a wave Use the equation v = f x λ Apply the relationship between wavelength, frequency and velocity
The Mexican wave Task: As we go around the room – what has been transferred? How can we define the term ‘wave’?
The Mexican wave Task: As we go around the room – what has been transferred? How can we define the term ‘wave’? Energy has been transferred. A wave is something that transfers energy from one place to another with no net transfer of matter.
Wave diagrams Task: Use the hints to help you label your wave diagram Keywords: • wavelength = the distance between two peaks • amplitude = the height of a peak • peak = the highest point of the wave • trough = the lowest point of the wave • frequency = the number of peaks
Wave diagrams Peak Wavelength Amplitude Frequency Trough Task: Selfassess
Checkpoint Task: Match up the key terms Pitc h Amplitude Number of waves Volume Frequency Height of waves
Checkpoint Task: Match up the key terms Pitc h Amplitude Number of waves Volume Frequency Height of waves
Spot the difference Task: Which has the lowest volume? A B Sound B has lower peaks – this means it has a lower amplitude – this means it has a lower volume
Spot the difference Task: Which has the highest pitch? A B Sound B has more peaks – this means it has a higher frequency – this means it has a higher pitch
Largest amplitude? A. B. C.
Largest wavelength? A. B. C.
Smallest wavelength? A. B. C.
Smallest amplitude? A. B. C.
Calculating wave speed Task: Complete the formula triangle for this equation Challenge: Frequency = ? Wavelength =? wave speed = v frequency = f wavelength = λ wavespeed frequency x wavelength Frequency = wave speed/wavelength Wavelength = wave speed/frequency
Teacher model The wavelength of the wave is 0. I m. Its frequency is 2 Hz. Calculate the speed of the wave. Show clearly how you work out your answer and give the unit. . . . . . . . . . . . . . . . . . . . . . . . Speed of wave
Teacher model The wavelength of the wave is 0. I m. Its frequency is 2 Hz. Calculate the speed of the wave. Show clearly how you work out your answer and give the unit. . . . . . . . 0. 1 m x 2 Hz = 0. 2 m/s. . . . . . . . . . . . . . . . Speed of wave
Your turn The wavelength of the wave is 0. 5 m. Its frequency is 5 Hz. Calculate the speed of the wave. Show clearly how you work out your answer and give the unit. . . . . . . . . . . . . . . . . . . . . . . . Speed of wave
Your turn The wavelength of the wave is 0. 5 m. Its frequency is 5 Hz. Calculate the speed of the wave. Show clearly how you work out your answer and give the unit. . . . . . . . 0. 5 m x 5 Hz = 2. 5 m/s. . . . . . . . . . . . . . . . Speed of wave
Rearranging the equation – Teacher model 1. Twelve waves pass an observer in four seconds. What is the frequency of the waves? Show clearly how you work out your answer and give the unit. . . . . . . . . . . . . . . . Frequency = . . . . (3)
Rearranging the equation – Teacher model 1. Twelve waves pass an observer in four seconds. What is the frequency of the waves? Show clearly how you work out your answer and give the unit. . . . 12 / 4 = . . . . 3 Hz. . . . . . . . Frequency = . . . . (3)
Rearranging the equation – Your turn 1. 15 waves pass an observer in 3 seconds. What is the frequency of the waves? Show clearly how you work out your answer and give the unit. . . . . . . . . . . . . . . . Frequency = . . . . (3)
Rearranging the equation – Your turn 1. 15 waves pass an observer in 3 seconds. What is the frequency of the waves? Show clearly how you work out your answer and give the unit. . . . 15 / 3 = . . . . 5 Hz. . . . . . . . Frequency = . . . . (3)
Calculating wavespeed Wave speed Frequency (Hz) Wavelength (cm) Wavelength (m) 10 Hz 10 cm 0. 1 2. 5 Hz 10 cm 30 Hz 2 cm 50 Hz 1 cm 200 Hz - 10 1000 Hz - 5 (m/s)
Calculating wave speed Wave speed Frequency (Hz) Wavelength (cm) Wavelength (m) 10 Hz 10 cm 0. 1 1 2. 5 Hz 10 cm 0. 1 0. 25 30 Hz 2 cm 0. 02 0. 6 50 Hz 1 cm 0. 01 0. 5 200 Hz - 10 2000 1000 Hz - 5 5000 (m/s)
Rearranging the equation Wave speed Frequency (Hz) Wavelength (m) 0. 6 24 0. 6 30 0. 6 12 0. 6 20 (m/s)
Rearranging the equation Wave speed Frequency (Hz) Wavelength (m) 0. 6 24 0. 025 0. 6 30 0. 02 0. 6 12 0. 05 0. 6 20 0. 03 (m/s)
Objective: Understand the difference 26/11/2020 between transverse and longitudinal waves OUTCOMES: Developing State examples of transverse and longitudinal waves Progressing Describe the oscillations in transverse and longitudinal waves Advancing Explain why sound waves are longitudinal and water waves are transverse Analyse models used to show transverse and longitudinal waves Excelling
Transverse vs. Longitudinal Task: Using the video and the demonstration, identify the differences between light and sound waves. Ligh t Sound Both travels the fastest travels in longitudin waves al transverse peaks, troughs, wavelength and transfers energy frequency from one place to another must travel through matter does not need moves up and matter to down travel moves back and travels in a forth ray travels slower
Transverse vs. Longitudinal Task: Using the video and the demonstration, identify the differences between light and sound waves. Ligh t does not need matter to travel transverse travels the fastest moves up and down peaks, troughs, wavelength and frequency travels in a ray Sound Both travels slower transfers energy from one place to another travels in waves longitudinal moves back and forth must travel through matter
Direction of wave travel Longitudinal = the vibrations are along the same direction as the direction of travel Transverse = the vibrations are at right angles to the wave motion
Checkpoint Task: Are water waves transverse or longitudinal? Justify your choice.
Checkpoint Task: Are water waves transverse or longitudinal? Justify your choice. Water waves are transverse as the wave moves up and down at a right angle to the direction of movement.
Objective: Understand the reflection of 26/11/2020 light OUTCOMES: Developing Progressing State the law of reflection Describe how light is reflected from a plane mirror to create an image Advancing Construct a ray diagram to illustrate reflection of a wave at a boundary Excelling Draw sensible conclusions from experimental results
Reflection Task: Label the diagram with the missing keywords. Keywords: • Normal ray • Incidence ray • Reflected ray • Mirror • Angle of incidence • Angle of reflected Challenge- What other words can be written on vehicles?
Angle of reflection 1. What was the initial ray called? 2. What do we call the line at a 45 degree angle to the mirror? 3. When drawing ray diagrams, how do you represent a mirror? 4. Using your data, what is the law of reflection? Challenge: What kind of wave is reflected at a mirror?
Angle of reflection Incidence What was the initial ray called? ray 1. 2. What do we call the line at a 45 Normal line degree angle to the mirror? 3. When drawing ray diagrams, how do you represent a mirror? 4. Using your data, what is the law Angle of incidence is equal to the angle of reflection? Challenge: What kind of wave is reflected at a mirror? Light wave - Transverse
OBJECTIVE: Understand the refraction of light OBJECTIVE: Always use a ruler! 26 November 2020 OUTCOMES Developing State what refraction is (Good) Progressing Describe how light is refracted (Even better) Advancing (Outstanding) Excelling Construct a ray diagram to illustrate refraction of a wave at a boundary Justify sensible conclusions from experimental results Reminder: knowledge organisers, pencil cases and planners out!
Dense medium or not? Glass block Water Ai r Task: Identify which of these is the most dense. Challenge: Explain what you think happens when light goes from a dense medium to a less dense medium.
Dense medium or not? Glass block Water Ai r Both the glass block and water are dense, air is the least Task: Identify which of these is the most dense. When light enters a less dense medium, the light speeds up Challenge: Explain what you think happens when light causing the direction of the wave to change. goes from a dense medium to a less dense medium.
Checkpoint Task: Explain why spear fishers don’t aim exactly for where the fish appears to be. Challenge: How could they improve their aim.
Checkpoint Task: Explain why The actual fish is closer spear fishers than the apparent image don’t aim exactly as light has refracted for where the fish and bent. appears to be. Challenge: How could they improve their aim.
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