S4.10.1 For the adult
Kinds of waves
Mei flicks one end of a long rope, and a bump runs to the other end. What actually moved along the rope?
What this chapter teaches
A wave carries energy from place to place and not the material it passes through. In a transverse wave the vibration is across the way the wave travels, in a longitudinal wave it is along it. Sound is longitudinal. Light is transverse and needs no medium.
Three questions to ask
There is no one right wording. Listen for the idea.
- A cork floats on a pond and ripples pass it. What happens to the cork, and what does that show about waves?
- How do the vibrations differ in a rope wave and in a sound wave?
- Why can sunlight cross space when sound cannot?
After the chapter, the learner can
- Compare transverse and longitudinal waves with a rope and a spring
- Explain that waves carry energy, not matter
What they copy into their notebook
A wave carries energy, not material. Transverse: vibration at 90° to travel (rope, light). Longitudinal: vibration along travel (sound, spring). Light needs no medium.