Waves
L.O. To describe the transfer of energy by waves
To use the Keywords associated with waves
To calculate any of the three quantities
associated with waves
Starter
1 Write down a definition for Transverse Waves
and Longitudinal Waves
2 Complete the activity labelled starter on the
worksheet.
You have 5 min
Task
• Using pages 216 and 217 Complete the
worksheets
You have 10 min
http://www.youtube.com/watch?v=VtmFvHeFpVs
3:50 min
http://www.youtube.com/watch?v=U8XcPOvKdvA
Q4 from the Book
Worked Example Questions
1 What is the Wave Speed (v) if:a) X = 40m, t = 2s
Follow on task:- Complete Q4 from P217
b) X = 35m, t = 0.5s
Extension:2 What is the time (t) if:3 The wavelength of a sound wave is 2.8 cm. Calculate
a) X = 8m, v = 4m/s
the frequency of the waves in hertz.
b) X = 10m, v = 50m/s
4 Convert the following wavelengths into metres:
3 What is the Wave Speed if:a
a radio wave of wavelength 3.5 km
a) λ = 10m, f = 100Hz
b
a microwave of wavelength 5 cm
b) λ = 6m, f = 200Hz
c
a sound wave of wavelength 120 mm.
4 What is the frequency if:5 Ripples on the surface of water are noticed to travel
a) λ = 2m, v = 2000m/s
560 cm in 54 seconds. Calculate the speed of these
waves in metres per second.
b) λ = 4m, v = 800m/s
6 a
Use your answers from question 4 to calculate
the frequency of each of the three waves.
The units needed for wave calculations are metres, seconds, metres per
second and hertz.
1 kHz = 1000 Hz
1 MHz = 1 000 000 Hz 1 m = 100 cm = 1000 mm.
b
From question 4, identify which are longitudinal
waves and which are transverse waves.
Written Question
Surfers like to have a long ‘fetch’ (Distance over
which the waves have been formed), the longer
the fetch the bigger and more powerful, and
faster the ride.
Explain using as much detail as possible how a
surfer might calculate the wave speed. Include
information on two ways that this could be
done.
Include working using estimated values
Marking
• Reference to
• Counting Waves as they pass a particular point to
determine frequency
• Estimating or measuring the distance between wave
crests
• Using numbers generated to calculate Wave speed
• Timing surfer over a known distance to determine
distance and time quantities for calculations
• Reference to correct units
• Working present using e.g. numbers