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.
Life Cycle. The life cycle of a louse begins as an egg, also called a nit. The nit is a 1mm whitish-yellow speck that attaches itself firmly to an individual hair strand close to the scalp. After 7 to 10 days, the nit hatches and becomes what is known as a nymph, or a young louse.s long as thereâs a food source readily available, an adult louse can live for as long as 30 days on a human. However, this short lifespan is perpetuated by the constant laying of eggs. Female lice lay up to six eggs each day.