UNIT OVERVIEW
This unit introduces longitudinal waves, where particles move back and forth in the same direction as the wave travels. This is different from transverse waves, which you studied in Term 1, where particles move at right angles to the wave direction.
Sound is the most important example of a longitudinal wave. Every sound you hear—from a whispered conversation to a loud siren—travels as compressions and rarefactions through air or other materials.
What You Will Learn:
- How longitudinal waves differ from transverse waves
- The key properties: wavelength, frequency, amplitude, period, and wave speed
- How sound waves travel through different media
- What determines pitch, loudness, and quality of sound
- Applications of ultrasound in medicine and industry
- How to calculate wave properties using mathematical relationships
Real-Life Applications:
Medical Ultrasound: Doctors use high-frequency sound waves to create images of babies during pregnancy and to examine internal organs—safely, without radiation.
Sonar Navigation: Ships use sound pulses to measure ocean depth and detect underwater objects. Fishing boats locate schools of fish using similar technology.
Musical Instruments: Every musical sound is a longitudinal wave. Understanding wave properties helps explain how instruments produce different notes.
Industrial Testing: Factories use ultrasonic testing to check for cracks in metal products without destroying them.