A child drops a stone into the middle of a still pond. Ripples spread out across the surface of the water.
A plastic duck is floating on the pond, several metres from where the stone lands.
Describe how the duck moves as the ripples pass it.
Explain how the movement of the duck shows that it is the wave, and not the water, that travels across the pond.
State what the ripples transfer from where the stone lands to the duck.
A teacher holds a lit candle in front of a loudspeaker that is playing a loud, low-pitched note.
Describe what would be seen that shows that the sound wave, and not the air, travels away from the loudspeaker.