Observing Meteorological Phenomena

E V A L U A T I O N

E s s a y s
Your essays will be evaluated out of 10 and will be graded in such a way that the class mean is about 6 to 7 (thus approximately half the papers should get 6 or below and about half should get 7 or above).

• 9-10 will be reserved for an essay that could be published in Weatherwise with at most minor editing.

• 5 -8 will be given to an essay that has a good picture and a generally appropriate explanation, but one with enough ambiguities, silliness or redundancies that you sometimes have to work hard to extract the essence.

• 0-4 will be given to an essay where the explanation is lacking, either because it is often wrong or is missing, and where the writing is sloppy and confusing.

In preparing and reviewing your essay, you should carefully consider the following questions, because these are some of the same questions that your instructor will raise while grading your work.

• Do you make reference to the picture and point out the features that are to be discussed?

• Is the phenomenon being discussed clearly visible in the picture?

• Do you explain the phenomenon by using physical principles, or do you just define and describe it? Do you offer undefined terminology as a substitute for offering an explanation (the blue sky is caused by Rayleigh scattering)?

• Did you anthropomorphize; that is, did you attempt to explain the behavior of the phenomenon by ascribing human characteristics to it? For example, do you suggest that the atmosphere attempts to, or wants to, do something? A physical system has no wants and does not attempt to do anything; to suggest that it does so is an admission that you don't know how to describe the actual processes.

• Is your content appropriate? For example, in discussing a phenomenon, you might have devoted many words to explaining aspects that cannot be seen in the picture (just because they were treated by a reference book), but have left unexplained features that appear prominently.

• Is your writing clear? How often is the text ambiguous or, worse, wrong? Look for situations where you might be tempted to defend you sloppy writing with the excuse, "Well, you knew what I meant." Make sure that you never have to offer that rationalization. Look particularly for any ambiguous antecedents of pronouns and for mismatches between the subject and the verb.

• Is the writing concise? Do you say the same thing two or three times or introduce irrelevancies? Are there superfluous words (nouns turned into adjectives and a new irrelevant noun introduced: thunderstorm situation, the sun-dog effect), or ignorance-revealing redundancies (solar insolation, relatively fewer, sufficiently enough, plan ahead, completely surrounded)?

• Do you uncritically repeat illogical things from other authors (or instructors): warm air can hold more water vapor than cold air; the air (parcel) condensed; the clouds trap radiation; it reradiates; the buoyant parcel is unstable; the ground starts to radiate at sunset, the temperature was warm?

• Is your explanation appropriate for the phenomenon shown in the picture: your discussion is about radiation fog (or stratocumulus), but your picture shows smoke (or altocumulus); your discussion is about wave clouds, but your picture shows only billows; your discussion is about halos, but your picture only shows lens flare?

• If you have correctly identified the phenomenon in the picture, is your explanation scientifically correct: your discussion is about contrails but you claim that the condensation is a result of the cooling of the moist exhaust; your discussion is about the blue of snow but you claim that it arises in the same way as the blue of the sky?

• Do you serve up half truths as the whole truth? Look closely at any unqualified categorical assertions to see if that which is merely typical is being offered by you as being universal.

• Do you confuse definitions with explanations?

• Do you make appropriate word choices? There is a tendency on the part of some essayists to use unfamiliar or technical words in an attempt to impress the reader. This often leads to silliness as the word, effect, is confused with affect; imply with infer; parcel with air mass; refraction with diffraction.

• Is your writing as simple as it can possibly be and still tell the story? Your instructor is impressed when you illuminate a complex idea with simplicity and concision; he is not impressed when you obscure a simple idea with complexity and pomposity. Be guided by Ockham's razor.

Ockham's razor

Do not multiply entities without necessity.

William of Ockham (1285-1349)

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