Lecture on Transverse and Longitudinal Waves

Objectives

• Describe differences between transverse and longitudinal waves.
• State examples of these types of waves.
• Describe evidence that when waves move, it's the wave that moves and not the medium.

Types of Waves

All waves are categorized as either:

1. Transverse Waves
2. Longitudinal Waves

Examples

• Transverse Waves: Ripples on the surface of water.
• Longitudinal Waves: Sound waves traveling in air.

Key Facts About Waves

• All waves transfer energy from one place to another.
  • Ripples transfer kinetic energy.
  • Sound waves transfer sound energy.

Transverse Waves

• Example: Ripples on the surface of water.
• Oscillations: Movements up and down.
• Direction of Energy Transfer: Perpendicular to oscillations.
  • Perpendicular means at right angles.
• Visual Representation: Wave moves sideways, oscillations are up and down.

Longitudinal Waves

• Example: Sound waves traveling through air.
• Oscillations: Parallel to the direction of energy transfer.
• Air Particles Movement:
  • Compressions: Regions where particles are close together.
  • Rarefactions: Regions where particles are spaced out.
• Medium Requirement: Requires a medium (air, liquid, or solid) to travel.
  • Not all transverse waves require a medium.

Evidence: Wave Movement vs. Medium Movement

• It's the wave that travels, not the medium:
  • Transverse Waves: Using a slinky, the red dot (representing a point or water molecule) oscillates up and down, does not travel along the medium.
  • Longitudinal Waves: The red dot (representing an air particle) oscillates side to side, does not travel through the medium.

Additional Resources

• Find practice questions on transverse and longitudinal waves in the revision workbook available through the provided link.