Élongation en fonction de la distance et du temps
Two wave graphs look almost identical but mean completely different things. This simulation draws displacement against distance and displacement against time together, making clear that one shows wavelength and the other shows period.
Comment utiliser cette simulation
- Display both graphs simultaneously
- Change the frequency and wavelength independently
- Select which particle the time graph follows
Ce qu’il faut observer
- The distance graph repeats over a wavelength; the time graph over a period
- Both are sinusoidal and easily confused if the axis is not checked
- Wave speed comes from combining the two, not from either alone
La physique derrière
A displacement–distance graph is a snapshot of the whole wave at one instant, so the repeat distance is the wavelength λ. A displacement–time graph follows one particle over time, so its repeat interval is the period T. The two are linked by the wave equation v = λ/T = fλ, which is why you need both graphs to find the speed.