Joby's ripple tank has two small rods that tap the water side by side in the same steady rhythm. Circular ripples spread from each rod and run through each other.
Each rod sends out its own set of ripples. Where the two sets keep overlapping, what does the water do?
The water settles into a pattern. Along some lanes, the ripples are extra big.
Along other lanes, the water stays nearly still.
The pattern holds its shape. As long as the two rods keep tapping steadily, the big lanes stay big and the still lanes stay still.
The pattern is superposition at work everywhere at once, because when two waves overlap, the displacement at each point is the sum of the individual displacements, and the waves then pass through each other unchanged.
In a big lane, the overlap is constructive over and over. In a still lane, it is destructive over and over.
The ripples themselves pass straight through each other. Only their sums make the pattern.
Two paddles tap a pond's surface side by side in the same steady rhythm. Ilka sees lanes of big ripples separated by lanes of nearly still water, and the lanes hold their positions. What is this pattern called?
Waves from two sources overlap here.
The overlap produces a stable pattern of reinforced and canceled regions.
The pattern is interference.
One of the two paddles stops. What happens to the pattern?
The pattern needs waves from two sources overlapping.
With one source gone, there is no second set of ripples to sum with.
The lanes disappear; only ordinary ripples from the working paddle remain.
Two steady sources send ripples across the same stretch of water. What appears where the two sets of ripples overlap?
Both sources keep vibrating steadily. What happens to the pattern's still lanes over time?
Waves from two sources overlap and produce a stable pattern of reinforced and canceled regions. What is this pattern called?
Which statement describes interference?
Ilka watches two garden fountains dripping steadily into the same pool. Between them, lanes of big ripples alternate with lanes of nearly still water, and the lanes hold their places. What has formed?
In a two-fountain pattern, some lanes of water stay nearly still even though ripples from both fountains keep arriving. Why?