After the Alphabetic Code: How Comprehension Grows in Subject Classrooms

Phonics has earned its central place in early reading instruction across the UK, and the evidence for systematic synthetic phonics is substantial. The alphabetic code is not an optional extra: pupils who cannot decode print will struggle to learn from it. Yet decoding is a means, not an end. Once words can be lifted from the page, comprehension draws on a different set of resources — vocabulary, background knowledge, inference and the management of cognitive load. In science lessons, those demands arrive early and rarely relax.

The simple view, and the complicated classroom

The Simple View of Reading offers a useful starting point: comprehension is the product of decoding and linguistic comprehension. Neither side compensates fully for the other. A pupil who decodes fluently but knows little about the topic, or who cannot follow complex syntax, will not automatically understand an explanation of evaporation or electromagnetism. Scarborough's reading rope adds texture: word recognition and language comprehension are woven from strands such as vocabulary, background knowledge, syntax, verbal reasoning and working memory. The metaphor is apt because the strands are interwoven in practice, not taught in isolation.

Vocabulary is a network, not a list

Science texts are dense with specialised terms. Some, such as photosynthesis or voltage, are tier three words that belong to the discipline. Others, such as process, evidence, contrast or factor, are tier two words that carry academic work across subjects. Teaching a list before reading can help, but word knowledge is more than matching a term to a definition. Pupils need to see words in use, connect them to related words, and practise retrieving them. Morphology matters: understanding that bio-, -logy, therm- or -meter carry meaning gives pupils a way into unfamiliar vocabulary. In primary classrooms, this can begin orally and through practical experience. In secondary science, it should be planned into schemes of work rather than left to chance.

Background knowledge and the work of inference

Comprehension is easier when a reader already knows something about the subject. That is not a counsel of despair for teachers of disadvantaged pupils; it is an argument for building knowledge deliberately. A text about rock formation assumes some sense of time, pressure and change. A diagram of a circuit assumes that pupils understand what a complete path means. Where knowledge is thin, inference becomes heavier. Proficient readers fill gaps almost invisibly; developing readers may not notice that a gap exists. Science texts often rely on causal chains, comparisons and abstract processes, so the inferential load is high. Primary teachers can build the groundwork through direct experience, narrative and carefully sequenced explanation. Secondary teachers can use retrieval starters, concrete examples and visible models before asking pupils to read independently.

Cognitive load and the design of text

Working memory is limited, and reading a demanding science text makes multiple calls on it at once: recognising words, holding sentences in mind, linking ideas, interpreting diagrams and monitoring meaning. Cognitive load theory suggests that materials should reduce unnecessary demands so that pupils can attend to the science. That does not mean dumbing down. It means designing texts and tasks with coherence. Headings, signalling words, short paragraphs and integrated diagrams can help. So can pre-teaching essential vocabulary and checking that pupils can read the text fluently before asking them to analyse it. Readability formulas are a weak guide on their own: a short sentence containing an unfamiliar concept can be harder than a longer narrative that supplies context.

What it looks like in a lesson

EEF guidance on reading comprehension and subject-specific literacy points towards explicit teaching of strategies such as prediction, questioning, clarifying and summarising, but not as a generic checklist. Strategies are most useful when they are modelled, practised and then faded. In a science lesson, that might mean the teacher reads a paragraph aloud while thinking about how the diagram connects to the words; pupils then read a parallel paragraph in pairs with a small set of text-dependent questions. Ofsted's research reviews have similarly emphasised the importance of subject-specific reading and the need for curriculum thinking about vocabulary and text. The practical point is that reading in science is not an interruption to content teaching. It is part of it.

Diagnosis matters

When pupils struggle with a science text, the cause may be decoding, fluency, vocabulary, background knowledge, inference or attention. A quick assumption that the problem is phonics can mislead in Key Stage 3, just as an assumption that a fluent reader must understand can mislead in Key Stage 2. Checking fluency and asking pupils to explain a sentence in their own words are simple diagnostic moves. They help teachers decide whether to support word reading, language comprehension or both.

Beyond the first step

None of this diminishes phonics. It places phonics within a larger account of reading development. The science of reading is not a single lesson or a single phase; it is a body of evidence about how readers build meaning from print. For subject teachers, the implication is not that every lesson must become a reading lesson. It is that science texts make particular demands, and those demands can be taught. Vocabulary can be planned, knowledge can be built, inference can be modelled and cognitive load can be managed. Decoding opens the door. Comprehension is what pupils do once they walk through it.