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Observation and Explanation in Science

A website relevant to this page: http://www.ems.psu.edu/~fraser/BadScience.html

Basic to the way that science proceeds is the separation between observation and explanation. Scientists observe natural phenomena and attempt to describe them accurately. Accurate observation provides the indispensable platform upon which hypothesis, theory and ultimately explanation must be based.

Learning to keep observation and explanation separate is apparently one of the most simple skills to grasp, and yet one of the most difficult to carry out in practice. It is hard, for example, when describing a hand specimen of a rock or how the partial pressure of oxygen is thought to have varied in the Earth's atmosphere over geological time, to stop with the description and not go on to try to explain it. Isn't science about explaining nature, after all?

Well, of course it is! But we can only hope to arrive at a correct understanding of a natural phenomenon if we have first accurately observed it and described its features. In science, it has been said, if a thing has not been measured then we know nothing about it.

Any student of science must learn to observe and describe first, and to offer explanations later! The sequence of steps Observation Ô Description Ô Explanation is a fundamental procedure in all branches of science.

In the short section below I try to make explicit what the application of the rule Observation Ô Description Ô Explanation means in S260, Geology.

S260, Geology

Observation Ô Process Ô Environment

Block 4, Surface Processes, opens on page 1 with a section on the logical thought sequence of Observation Ô Process Ô Environment. Section 1 says that throughout the course "you have been introduced to the concept that careful observations on rocks can be used to determine the processes that formed them and the possible environments in which these processes may have occurred." Observation Ô Process Ô Environment is S260's way of saying Observation Ô Description Ô Explanation, applied to the interpretation of rocks.

In no other Open University science course is the importance of learning to follow the rule of Observation Ô Description Ô Explanation made more explicit. You will learn to apply the rule to different geological phenomena in each part of the course, and you will practise it in your TMAs and in the exam. If you choose to do Summer School you will practise it in the field. Your tutor will make it a feature of tutorials.

Essentially, you must resist the temptation to offer explanations or identifications until you have marshaled the evidence. You will have accomplished this when you can use your observations to defend your diagnosis against challenges. Here are some examples:

	When examining a rock in hand specimen,
	When examining a fossil,
	When faced with an exposure of sedimentary rocks in the field, observe and make notes of any structures you can see, any fossils you can find, the features of the rocks themselves, their relationships to other rocks in the area, etc. A good geologist will gather all the evidence he/she can find before attempting to diagnose the depositional environment in which the rocks were laid down.
	Identify the features of a volcano, such as the types of lavas it erupts, the types of eruptions that occur, the types of rocks it produces, the shape of the volcanic cone (if any!) and its location in relation to other major geological features on a regional scale, before you attempt to state what processes acted to produce the volcano.

But geologists Make It Look So Easy! You may feel that your tutor and other geologists you meet skip over the Observation Ô Description Ô Explanation procedure and go straight for the Explanation. How often you will see your tutor pick up a rock and say, "Aha, that's a basalt!" I can assure you, however, that they do not skip any steps: they merely go through them quickly, based on experience. In tutorials and at Summer School you will have many opportunities to use your own observations to challenge what the tutors say, and to point out features that no one had seen before, even though a site may have been visited by OU groups for many years. And if you attend Summer School you will almost certainly observe tutors arguing about how to interpret the geology that they take you to see!

If you observe the procedure of Observation Ô Description Ô Explanation (or Observation Ô Process Ô Environment as S260 calls it) then your opinions will carry weight, in tutorials, in TMAs, in the exam, and in the field. Geology is a discipline in which anyone, including a student on his/her first field trip, can make a genuine contribution. And part of the fun of S260 is to see if you can make your tutor confess that she/he is stumped!

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