Labs / Physics
Waves & Interference
Two point sources send out circular ripples that overlap. Where crests meet crests the water heaves in bright bands; where a crest meets a trough it cancels into a dark line. Drag either glowing source, stretch the spacing, or dial the wavelength and watch the pattern rearrange.
λ 2.5 cmd 8.0 cmfringes 7
What to try
- Slide the sources farther apart. Do you get more dark lines or fewer?
- Shrink the wavelength while keeping the spacing fixed. Which way do the fringes crowd?
- Freeze the motion. Can you trace a single dark line from one source all the way to the edge?
- Drag the two sources on top of each other. Where did the interference pattern go?
- What ratio of separation to wavelength gives you exactly one bright band straight down the middle?