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.
Not all light is in the visible spectrum, which is the light you can see. There are many kinds of electromagnetic waves that you can't see. Just look at the spectrum below. When we talk about a light detector, we are referring to any instrument that detects electromagnetic radiation.