Final answer:
During an experiment, it's essential to include descriptions of the appearance of any chemicals used, any changes, and any non-changes in the system. These observations underpin the scientific process, from hypothesis to experiments, and contribute to reproducibility in research.
Step-by-step explanation:
When making observations during an experiment, the following must be included:
- Descriptions of the appearance of any chemicals used.
- Descriptions of any changes in the system following an action.
- Descriptions of any non-changes in the system following an action.
Observations can be qualitative such as noting that sulfur crystals are yellow or quantitative such as measuring the temperature change in a reaction. Making detailed and accurate observations is crucial as they serve as a basis for forming a hypothesis, conducting experiments, and eventually summarizing the results in a scientific law. They should be thorough to allow reproducibility in scientific research. Recognizing changes, like temperature changes or color changes, and non-changes, like the absence of expected bubbles, can indicate whether chemical reactions have occurred.