After this lesson, you should be able to:

• Describe a sound wave as a longitudinal wave
• Link sound waves to regular variations in the pressure of the medium
• Justify the relationship between the speed of sound waves and the properties of the medium (for gases, liquids and solids)
• Explain the concept of an echo
• Use the wave equation to solve problems with sound waves that include applications such as sonar, ultrasounds and bats and so on
• Relate characteristics of sound waves, such as pitch and loudness to familiar characteristics of waves, such as frequency and amplitude
• Explain what ultrasounds are in terms of frequency and describe some of their uses