Types of check valves. A ball check valve is a check valve in which the closing member, the movable part to block the flow, is a spherical ball. In some ball check valves, the ball is spring-loaded to help keep it shut.
(October 2016) Learning is the act of acquiring new, or modifying and reinforcing existing, knowledge, behaviors, skills, values, or preferences which may lead to a potential change in synthesizing information, depth of the knowledge, attitude or behavior relative to the type and range of experience.
a form of behaviour modification involving the association of two or more events, such as between two stimuli, or between a stimulus and a response. In associative learning, an animal does learn to do something new or better (1994, p. 38, italics mine). There are two broad categories of associative learning: