The formula is used to measure the speed of ocean waves, like tsunamis, that have very long wavelengths relative to the depth of the water. Tsunamis can have wavelengths greater than 700 kilometers (the average ocean depth is 3-4 kilometers). The formula estimates the tsunami's speed while it is in deeper waters (as it approaches shallower coastal waters, the tsunami slows down, its wavelength shortens, and its height increases).
Head lice and their eggs (nits) soon perish if separated from their human host. Adult head lice can live only a day or so off the human head without blood for feeding. Nymphs (young head lice) can live only for several hours without feeding on a human.
Gestation time for head lice is 10 days from the point that a female lays the eggs and the nits hatch.An adult can live for up to 30 days on its host. If bedding and other items are not properly treated, eggs can hatch and a nit can reinfect a host. add a comment.nswer by mcmario2007 (786). The gestation time for head lice is approximately ten days and the best way to get rid of the lice is to use a proper shampoo meant to exterminate head lice. add a comment.