The faster a sound wave travels, the more distance it will cover in the same period of time. If a sound wave were observed to travel a distance of 700 meters in 2 seconds, then the speed of the wave would be 350 m/s. A slower wave would cover less distance-perhaps 660 meters-in the same time period of 2 seconds and thus have a speed of 330 m/s.
Melanoma Definition. Melanoma is a form of skin cancer that arises from melanocytes-the cells that produce pigment. Melanoma may begin in association with a mole. Melanocytes produce a pigment called melanin that gives the skin its colour and protects it from sun damage.
Melanoma is the most serious form of skin cancer. Even so, if diagnosed and removed while it is still thin and limited to the outermost skin layer, it is almost 100% curable. Once the cancer advances and metastasizes (spreads) to other parts of the body, it is hard to treat and can be deadly.