1. The problem statement, all variables and given/known data Waves with small wavelengths diffract less than those with longer wavelengths. Use this information to suggest why ultrasound is much better than ordinary waves for finding the depth of the sea [3 marks] 2. Relevant equations NONE 3. The attempt at a solution Ultrasound has a smaller wavelength than normal waves - hence wave is more concentrated on sea bed. 4. Problems The mark scheme includes the following two, extra, factors - amplitude decreases rapidly - range limited / cannot travel far. I presume that the last to factors refer to ordinary waves Is this next sentences correct: "the amplitude (energy) of an ultrasound wave decreases less rapidly than that of a normal wave - hence results will be more accurate and more responsive. Furthermore, ultrasound can travel further in water than normal waves"