A witness, or observer, is an individual who sees or experiences an event and can provide information about it. This role is crucial in various contexts, such as legal proceedings, where witnesses may testify about what they saw or heard. Their accounts can help establish facts and clarify circumstances surrounding incidents. In scientific research, an observer may record data or behaviors during experiments. This can include noting reactions in a study involving participants or monitoring changes in environmental conditions. Observers must remain objective to ensure their observations are accurate and reliable, contributing to the validity of the findings.