Definition - Constructivism. Definition of Constructivism. Constructivism is a theory of learning based on the idea that knowledge is constructed by the knower. based on mental activity. Learners are considered to be active organisms seeking meaning. Constructions of meaning may initially bear little relationship to reality (as in the naive theories of.
The visible spectrum is the portion of the electromagnetic spectrum that is visible to (can be detected by) the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light.
Our eyes are detectors which are designed to detect visible light waves (or visible radiation). Visible light is one of the few types of radiation that can penetrate our atmosphere and be detected on the Earth's surface. As we have seen from the section on the discovery of infrared, there are forms of light (or radiation) which we cannot see.