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Academic and Scientific Language.
Science texts use lots of unfamiliar terms. While these terms support
clear, precise communication for the initiated, they are like a foreign
language for students. Students need help learning to interpret
scientific vocabulary through the use of visual representations,
identification of common prefixes and suffixes, or discussion of the
different meanings words can have in different contexts.
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Logical Connectives.
Logical connectives, such as coordinating and subordinating conjunctions, help to clarify relationships.
Jack left and Jill arrived.
Jack left because Jill arrived.
Jack left even though Jill arrived.
Students need to learn the meaning of the logical connectives they encounter, but science textbooks for
children often present an opposite problem: missing logical connectives. In an effort to improve
accessibility for struggling readers, textbook editors may remove logical connectives, breaking complex
sentences to simple, independent clauses. This kind of simplification can be a double-edged sword,
though, according to linguistic research. When you change
The earth goes through different seasons because it tilts on its axis.
to
The earth goes through different seasons. It tilts on its axis.
You get rid of a complex sentence; but you also get rid of the main point: the because, the causal
relationship between the two clauses. Science teachers may need to help their students spot the
underemphasized relationships in science texts.
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Polysemy.
Many words have multiple meanings. While terms like power, organic, and theory
might have relatively fixed meanings when used in scientific discourse, these same
well-traveled words bring baggage from many other contexts. Students need to
learn the science-specific definitions of such words, and they also need to learn
how to interpret polysemous words appropriately according to context. For
example, only the third sentence below uses the word organic in its narrow
scientific sense:
Most of the scenes were organic to the plot of the movie, but the director left in a
few that seemed gratuitous.
When she took up organic farming, she stopped using synthetic pesticides and
fertilizers and turned her chickens loose to prey on the pests and manure the
crops.
Many organic compounds, such as hydrogen cyanide (HCN), are extremely toxic.
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Lexical Density.
The ratio of content words (nouns, adjectives, verbs, and adverbs) to
function words (pronouns, prepositions, auxiliary verbs, determiners,
exclamations, and conjunctions) is called lexical density. More content
words mean greater density. Compared to typical narrative texts that
students read, science texts tend to have high lexical density, with lots
of challenging vocabulary that defies skimming. Students need to
learn what the words mean, but even if they know the vocabulary they
must learn to read dense text relatively slowly, breaking, annotating,
reflecting, and rereading.
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Nominalization.
For the sake of efficiency, specialists in science and other fields often pack
descriptions of complex processes into single nouns, a process called
nominalization. The word nominalization is itself an example of nominalization,
standing in, as it does, for a complex linguistic practice.
Geologists can just toss off the term stratification instead of going into lengthy
descriptions of wind and water depositing layers (strata) of different material over
time. Chemists use words like evaporation, condensation, sublimation, and
deposition instead of getting bogged down in elaborate descriptions every time
they need to mention a phase change.
Nominalizations become transparent and helpful to the initiated, increasing the
density of information. But they can present an opaque barrier to students.
Nominalization conceals agency—who is doing what?—and converts concrete
events into abstractions. Students need their teachers to help them unpack the
meaning of nominalizations.
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Multimodality.
The content of science is a heavy burden for words alone to bear, and so
science texts resort to other of modes of communication as well. Chemical
symbols represent the elements, illustrations range from the relatively
concrete to the abstract and schematic, graphs and charts represent a
multitude of patterns, and mathematical notations capture systematic
relationships. Molecules can be represented in space-filling models to
emphasize their overall shape, ball-and-stick models to emphasize the
geometry of their bonds, or structural formulas that are a hybrid of text
and schematic illustration. The various representations in a science text
can reinforce each other, illuminate different aspects of a phenomenon or
idea, and meet the needs of students with various learning styles; but the
multimodality of these texts can also be challenging. Students must strive
to integrate and interpret multiple channels of a semiotic symphony.
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Passive Voice.
Scientific texts such as reports, explanation, and experimental write-ups
commonly employ the passive voice to bolster a sense of objectivity.
Ideally, the results of an experiment should not depend on who performs it;
data observed in nature should be a property of nature, not of the observer.
Scientists often use the passive voice (“the precipitate was filtered,” “radiation
was detected,” “fossilized remains were found below this strata”) to minimize
the sense of human agency in the phenomena they report. This absence of
agency is the opposite of what students are used to from reading, say, fiction
("Larry the lab tech heaved a sigh and, for the hundredth time, filtered the
precipitate").
One can debate whether the passive voice is overused in science writing (and
lots of other writing). But it is probably appropriate a lot of the time (tell us
about the precipitation reaction, not about Larry!), and in any case students
need to get comfortable reading it.
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Visualizations.
Scientific communication increasingly relies on visualizations, whether still, animated, or
interactive. The saying goes that a picture is worth a thousand words, and illustration can certainly
be an effective tool of science education. However, visual representations can also baffle or
mislead students. Teachers can help by providing explicit instruction on how to interpret visual
representations.
For example, where do students get the incorrect idea that the cycle of the seasons is caused by
variation in the earth’s distance from the sun throughout the year? One contributing culprit may
be the frequent schematic illustration of the earth’s orbit around the sun viewed in perspective,
from slightly above the earth’s plane of orbit. This perspective shows the earth’s orbit as an ellipse
with the sun at the center. Students may not understand the perspective in such images, and may
think that the exaggerated ellipse shows a “top” view (from solar north or south) of the earth’s
orbit.
It’s not that this way of illustrating the orbit of planets is bad. It can actually make it easier to show
how the tilt of the earth’s axis causes seasonal variation in sunlight in the earth’s northern and
southern hemispheres. The point is simply that pictures are not always as self-explanatory as we
may think they are. A picture may be worth a thousand words, but it may still call for additional
discussion.