Idea 1of 9Builds onCarried by motion
The pattern moves, the stuff stays
A ripple crosses a pond. Does the water go too?
Today you'll discover
- what actually travels across the pond
- what one bit of the water does
- the word for a travelling pattern
Think firstA pattern moves along a rope. Watch one marked bit
The pattern moves to the right. Where does the marked bit of rope go?
Predict first, then press Next. Watch the marked dot and only the marked dot.
A wavy line across the picture with one filled dot on it and a thin vertical guide through the dot. After a prediction, the frames advance: the crests move to the right while the dot rises and falls on its guide, faint ghosts marking where it has been in a vertical line. The last step asks what travels in a stadium wave.
See the whole ideathe big idea and the key word, in one place
The big idea
A wave is a travelling pattern; the medium only bobs.
Easy to get wrongA wave does not carry the medium along. If it did, the rope would pile up at the far end and the pond would empty on one side.
Key word
- wave
- a travelling disturbance that carries energy through a medium without carrying the medium along
About this modelThe pattern travels; the particle only bobs. One square of the drawing is 0.5 m.
The pattern travels; the particle only bobs. One square of the drawing is 0.5 m.
Ready to use it?
- Say what travels and what stays for a described wave.