Most people notice them in well-lit rooms or outdoors on a bright day. Often floaters are normal, but sometimes they're a sign of a more serious eye problem, such as retinal detachment, especially if you also see light flashes or a dark shadow come across the edge of your vision.
A Composite material (also called a composition material or shortened to composite, which is the common name) is a material made from two or more constituent materials with significantly different physical or chemical properties that, when combined, produce a material with characteristics different from the individual components.
Chemical substances are often called 'pure' to set them apart from mixtures. A common example of a chemical substance is pure water; it has the same properties and the same ratio of hydrogen to oxygen whether it is isolated from a river or made in a laboratory. chemical substance (also called a pure substance) may well be defined as any material with a definite chemical composition in an introductory general chemistry textbook. According to this definition a chemical substance can either be a pure chemical element or a pure chemical compound.