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.
Malignant melanoma (see the image below) is a neoplasm of melanocytes or a neoplasm of the cells that develop from melanocytes. Although it was once considered uncommon, the annual incidence has increased dramatically over the past few decades.