Measuring waves on a string
I can find the speed of waves on a string by measuring ‘standing wave’ patterns.
- Year 10
- AQA
Measuring waves on a string
I can find the speed of waves on a string by measuring ‘standing wave’ patterns.
Lesson details
Key learning points
- To find standing wave frequencies, increase the frequency of the oscillator until a standing wave pattern is seen.
- The wavelength of the waves can be found from the length of the oscillating string and the standing wave pattern
- The speed of waves on a string only depends on the properties of the wave medium (the string).
- For waves on a string, frequency and wavelength are inversely proportional
- Control variables are the quantities that must be kept the same during experiments so they don’t affect results.
Keywords
Standing wave - A standing wave is a stable pattern of oscillation that does not appear to travel across a wave medium.
Tension - Tension is the name for the force applied to a stretched string or rope. Without any tension a string or rope would be slack.
Inverse - Division is the mathematical inverse (opposite) of multiplication, so the inverse of ×2 is ÷2 (which can also be written as ×½).
Proportion - A proportion is an exact mathematical comparison, such as double, half (50%), triple, a third, quadruple, a quarter etc.
Control variable - Control variables are the quantities that must be kept the same during experiments so they don’t affect results.
Common misconception
Frequency or wavelength of waves on a string will affect the wave speed.
The speed of waves on a string only depends on the properties of the wave medium (the string) e.g. tension, density
Content guidance
- Risk assessment required - equipment
Supervision
Adult supervision required
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Waves on a string are waves.
Q2.What is 12 cm in metres?
Q3.Some waves on a string have a frequency of 3 Hz and a wavelength of 12 cm. How would you calculate the wave speed in m/s?
Q4.In experiments, what are the different types of variables?
Q5.When a wave travels along a string, what is the wave medium?
Q6.If waves of different frequencies and wavelengths all have the same speed, what happens if you increase the frequency of waves?
Assessment exit quiz
6 Questions
Q1.In an experiment, a variable that must be kept the same so it does not affect the results, is called a variable.
Q2.Which images show a standing wave on a string?
Q3.The length of string oscillating in this image is 90 cm. What is the wavelength of the waves?
