Waves

• There are 2 types of waves, tranverse and longitudinal.
• In tranverse waves, particles vibrate (oscillate) at right angles (perpendicular) to the direction of energy travel.
• In longitudinal waves, particles vibrate (oscillate) parallel to the direction of energy travel.
• Frequency - number of complete waves per second
• Frequency unit - Hertz - Hz
• Ultrasound - sound at a frequency above human hearing (20,000 Hertz)
• Echoes - Sounds that are reflected back from something solid.