Scientific Observation and Discovery are closely linked, but are different in many ways. It's important to know what these differences are and how to recogonize them.
First it's important to know what exactly observation and discovery are. Observation is the activity of receiving data via the senses, or through the measurements of scientific instruments. We observe everyday. When you smell a flower, hear a car whiz by, or notice how the wind picks up and carries leaves into the air. This form of observation is our natural way of observing the world, however, this form is usually prone to many interpretations about the world that can be false in many ways. This is where scientific observation through the use of measurements and predictions come in.
If we look at a glass of ice water for instance, we might observe that after awhile the outside of the glass starts to become wet. We asks ourselves, "How can this be?" because it seems upsurd to think that the liquid inside the glass has been transported to the outside of the glass. Our first observation, is that this is what has happened, that the liquid has mysteriously been moved to the outside of the glass of water.
However, it is only through scientific observation that we discern what is actually happening to the outside of the glass. We first make a hypothesis, a question about the observation made that can be either proven by experiment to be true or false. We then make measurements of the volume of water in the glass, and the consistency of water vapor in the air, to come to a conclusion about the mysterious new found liquid.
This is where Scientific Discovery comes in. After we have setup a series of measurements, and made our hypothesis, then performed the experiment, we come to our conclusion about the liquid. Through the testing, we have made a discovery. The liquid on the inside of the glass of water has not changed in volume, but rather the water vapor in the air has cooled against the surface of the icy glass and saturated to form droplets of water. The discovery then, is that we have discovered condensation.
This is how observation and discovery differ in science. It is the observations that scientists make and the questions that are born from them that lead to a discovery. In Science, you cannot simply infer that an observation made is the truth simply by observing it occurring, you must formulate a hypothesis and experiment to discover what is actually occurring. Just like our observation of the hypothetical glass of water, it was only until we tested our theories that we discovered the truth about the liquid on the outside of the glass.