what is stimulus in science

In science, a stimulus is defined as a detectable change in the physical or chemical structure of an organisms internal or external environment that triggers some sort of behavioral or physiological response. Stimuli can be external or internal, and they can be physical or chemical. Examples of stimuli include sights, sounds, smells, temperature changes, irritants, and changes in the body. In biology, sunlight can act as a stimulus for plants that helps them grow or move towards it, while high temperatures can activate the perspiration system in our bodies as a result of which our bodies cool down. In human behavior research, stimuli are the items used to evoke a reaction from participants or respondents in a study, and they may come in a range of formats including audio, visual, or physical. The purpose of the selected stimulus should be to make the research scenario more engaging and interactive for participants, and should mirror real-life as much as possible.