This document discusses data collection through observation. It defines observation as personally watching and interacting with research subjects to record what they do and say in their natural environment. This provides evidence to support research claims. Two main types of observation are discussed: participant observation, where the researcher takes part in activities, and non-participant observation, where the researcher detachedly watches without involvement. Methods include direct observation, indirect observation looking at past traces, continuous monitoring over time, and spot sampling at specific moments. The document concludes with an activity where students observe and record classmates' profiles.