Observation is the first step in the commonly taught scientific method, involving the systematic gathering of information through the senses and measurement. It gives scientists a phenomenon or pattern to investigate.
An observation might be qualitative, such as noticing that a liquid changes color, or quantitative, such as recording its temperature, mass, or volume. Scientific instruments extend the senses and make observations more precise: thermometers, microscopes, cameras, and sensors all turn events into records that other researchers can examine.
Observation leads naturally to questions and hypotheses. A researcher may notice that plants near a window grow differently, ask why, and propose a testable explanation involving light. The hypothesis is not the observation itself; it is a provisional explanation that makes predictions.
The textbook sequence is useful, but real science is iterative rather than rigid. Scientists often return to observation while testing a hypothesis, and existing theories influence what they notice and how they interpret data. Reproducibility also matters: observations should be recorded clearly enough that other investigators can repeat or independently assess them. “Conclusion” comes later, after evidence has been analyzed.