Regardless of the kind, every wave has an amplitude. Amplitude is the maximum displacement of points on a wave, which you can think of as the degree or intensity of change. This maximum displacement is measured from the equilibrium position.The picture below shows a diagram of a sine wave.mplitude is an important parameter of waves and is the maximum displacement of points on a wave. Stated another way, amplitude is the vertical distance between a peak or a valley and the equilibrium point. Frequency is the number of wave cycles passing a point per unit time.
Darkfield Digital Image Gallery Dogfish Shark Placoid Scales Dogfish sharks are small sharks belonging to one of three families: the dogfish shark family, Squalidae; the requiem shark family, Carcharhinidae; and the cat shark family, Scyliorhinidae.he green dogfish, along with several other members of the dogfish shark family, is luminescent. Scales are small plates that form part of the skin of certain animals. They provide protection from the environment and from predators. Sharks have placoid scales, bony, spiny projections with an enamel-like covering.
Placoid scales are found in sharks and rays, and can vary greatly in external appearance. Scales of a White Shark. Photographer: Sue Lindsay Â© Australian Museum. Unlike the scales of bony fishes, placoid scales do not increase in size as the fish grows, instead new scales are added between older scales.Placoid scales are often referred to as denticles.Each placoid scale consists of a flattened rectangular base plate which is embedded in the fish, and variously developed structures, such as spines, which project posteriorly on the surface.The spines give many species a rough texture.here are large differences in the development of these spines between different species. Placoid scales are composed of a vascular (supplied with blood) inner core of pulp, a middle layer of dentine and a hard enamel-like outer layer of vitrodentine.