Following the Unseen Arrow: How Pupils Track Meaning Across Science Sentences

Consider a sentence that might appear in a Key Stage 3 biology textbook: ‘When the enzyme binds to its substrate, it lowers the activation energy, and this allows the reaction to proceed more quickly.’ A confident reader barely notices the small words. A pupil who is still learning the science may pause at ‘it’. Does it refer to the enzyme, the substrate or the enzyme–substrate complex? The grammar permits more than one answer; the science narrows the field, but only if the reader already knows the field. The same question arises with ‘this’: is it the binding, the lowering of activation energy, or the whole preceding event? Such moments are not marginal. They are where comprehension either holds or slips.

Cohesion is not decoration

Science prose depends on reference chains. A noun is introduced, then picked up by a pronoun, a demonstrative or a definite noun phrase. ‘The catalyst’ becomes ‘it’; ‘the reaction’ becomes ‘this process’; ‘the two variables’ become ‘the former’ and ‘the latter’. These links allow writers to avoid clunky repetition and to build an argument across sentences. They also compress information. A phrase such as ‘the breakdown of the reactant by the catalyst’ turns a process into a thing, and the next sentence can refer to ‘this reaction’ as if its identity were settled.

For experienced readers, that compression is efficient. For pupils, it can hide the causal chain. The difficulty is not simply vocabulary. A pupil may know what ‘enzyme’ and ‘substrate’ mean and still misread the sentence because the referent of ‘it’ is unclear. Reference tracking draws on subject knowledge, grammatical knowledge and memory. It is part of reading science, not an optional polish applied afterwards.

Where the chain breaks

Reference problems appear in predictable places. Distance is one. A pronoun may sit several clauses away from its noun, with other possible candidates in between. Competition is another: two nouns of the same number and similar role make ‘it’ or ‘they’ ambiguous. Nominalisation adds a further layer. When a process is packaged as a noun phrase, pupils must recognise that the phrase refers to an event, not an object. ‘The interaction’ may mean binding, collision, attraction or a whole sequence, depending on the surrounding text.

Passive constructions can also obscure agency. ‘The solution was heated’ tells us what happened but not who or what did it. That may be appropriate in a method section, where the procedure matters more than the operator. In an explanation, however, the missing agent can make the causal story harder to follow. Definite noun phrases assume shared knowledge: ‘the process’ implies that the reader can identify which process is meant. If the pupil cannot, the sentence feels as though it has begun in the middle.

Making the chain visible

Classroom routines do not need to turn every science lesson into a grammar lesson. A few short, repeatable moves can make reference chains visible without slowing the curriculum to a crawl.

First, ask pupils to arrow the anaphor. Give them a short paragraph from the textbook or an exam-style explanation and ask them to draw a line from each pronoun or demonstrative to the noun phrase they think it refers to. Where there is disagreement, ask pupils to justify their choice using both grammar and science. This turns a silent reading problem into a visible one.

Second, use substitution as a test. Pupils replace ‘it’ or ‘this’ with their candidate noun phrase and reread the sentence. Does it still make sense scientifically? Does it still make sense grammatically? The test is quick, and it teaches pupils to use two kinds of evidence at once. It also shows that reference is not a matter of guessing what the teacher wants; it is a matter of constructing a coherent meaning.

Third, build a simple chain map. Two columns are enough: entities and processes. As pupils read, they list what is acting, what is acted upon and what is happening. Arrows can show causal links. A paragraph about enzyme activity might have ‘enzyme’, ‘substrate’ and ‘product’ in one column, and ‘binding’, ‘lowering activation energy’ and ‘reaction’ in the other. The map does not replace the text; it gives pupils a way to hold the text’s links in place.

Fourth, rewrite for clarity and compare. Ask pupils to turn an ambiguous sentence into two explicit sentences. Then discuss what was gained and what was lost. The explicit version may be easier to read but more repetitive. The original may be more elegant but more demanding. That comparison is valuable: it shows pupils that scientific writing involves choices, and that clarity is one aim among several.

Finally, model the process aloud. Read a paragraph and pause at a pronoun. Say what you think it refers to, why, and what you would check if you were unsure. A think-aloud makes expert reading visible and gives pupils language for their own uncertainty. It also normalises the act of rereading, which is often the simplest repair strategy available.

Reading science, not just reading

The aim is not to remove pronouns from science texts or to flatten every explanation into short, explicit sentences. Reference chains are part of how science writing works. They allow writers to connect claims, compress processes and build explanations that move beyond a list of facts. Pupils need to learn to follow those chains, not avoid them.

That learning belongs in science classrooms. It can be planned in five-minute routines, using the texts pupils already read. When teachers make reference visible, they are not adding an extra literacy burden to an overcrowded curriculum. They are helping pupils read the explanations that the curriculum depends on.