When a pebble is dropped into a liquid, small (capillary) waves travel outward, as shown in the figure below. The propagation speed of these waves (c) is a function of the surface tension (σ), the wavelength (λ) and the liquid density (ρ).
(a) Determine the dependence of propagation speed on the independent variables. When discussing the Loch Ness Monster hoax, were we right in saying that (for capillary waves) ''short waves travel faster''?
(b) Use the Loch Ness Monster photograph below to estimate the time between the pebble hitting the water and the photograph being taken. The visible portion of the ''monster'' is about 20 cm tall.
(HINT: Remember that you will only be able to obtain an order of magnitude estimate. Don't get too detailed in your analysis!)