As you do experiments, record all numerical measurements made. Data can be amounts of chemicals used, how long something is, the time something took, etc. If you are not making any measurements, you probably are not doing an experimental science project. Your Observations Observations can be written descriptions of what you noticed during an experiment, or problems encountered. Keep careful notes of everything you do, and everything that happens.
Observations are valuable when drawing conclusions, and useful for locating experimental errors.
Perform Calculations Do any calculations needed from your raw data to obtain the numbers you need to draw your conclusions. For example, you weighed a container. You then added some soil to the container and weighed it again. Not all experiments need a calculation section. However, if you do not have any calculations you may not be using the experimental scientific method.