Reflection and echo

Principle

In this experiment, the students observe the reflection of sound pulses in a glass tube - with a sealed and also with an open end. They record the signal and echo with a microphone and analyse the differences in the propagation time with the "measure Acoustics" software in order to determine the difference in distance between the signal and echo.

Benefits

• Experiment is part of an experiment set with a total of 22 experiments about generation, propagation and perception of sound, oscillations and waves
• Particularly appropriate as an experiment for first contact with physics in general
• With graphic student worksheets
• With detailed instructor information
• Optimized for tight schedules, i.e. minimum preparation time required

Tasks

Bats can determine the distance between themselves and other objects in their environment with the aid of ultrasound signals and, thereby, find their way. On ships, sonar is used to determine distances. In both cases, the effect of the echo is used, something that we are familiar with from our everyday lives. Simulate an echolocation process by measuring the distance that sound travels in a glass tube. Examine also whether the tube must be sealed for this purpose.

Learning objectives

• Sound pulse
• Signal 
• Echo
• Propagation time
• Sonar
• Echolocation