The diagram shows an experimental setup used to measure the wavelength of ultrasound waves in air.
A student aligns an ultrasound transmitter and a receiver on a track. The receiver is connected to an oscilloscope to display the wave signal.
To determine the wavelength, the student moves the receiver along the track and measures the distance from one position of maximum signal amplitude to the very next position of maximum signal amplitude using a metre ruler.
Explain how the student could improve their experimental method to obtain a more accurate value for the wavelength.