The two types of observation that are used in the scientific method are controlled and uncontrolled observation situations. In controlled situations, humans set up the situation, while in uncontrolled, the situation is determined entirely by nature.
An example of an uncontrolled situation would be observing the appearance of the moon. An example of a controlled situation would be using a variety of factors when planting seeds, such as different types of soil, different lighting and amounts of water. Nature acts upon both of these, though the latter is impacted by humans. Observations that are controlled in some manner can be compared to predictions afterwards. Observation is directly related to experimentation. Experiments are created based upon what we can observe with our five senses. This is why observation is crucial within the field of science.