Forget boosting maths skills, it’s words that hold the key to chemistry. Adding breadth and depth to students’ vocabulary will improve their understanding

We often hear comments like ‘Mary is good at chemistry because she is good at maths’ or ‘Jake will never do well in chemistry as his maths is so poor’ from both teachers and parents. The skill sets required for chemistry and maths seem intrinsically linked together in popular imagination.

However, I believe that linking chemistry and maths is, at secondary level, a false marriage. When students struggle with their maths skills in chemistry, they almost invariably complain: ‘I didn’t know what the question was asking me to do.’ And that is a weakness not in their maths, but in their literacy. They don’t have the literacy skills to decode the question and turn it into a format they can answer.

In your class

Download two vocabulary-based activities to use in your class with the Unscrambling definitions worksheet as MS Word or pdf and teacher notes as MS Word or pdf.

This gap between the literacy skills students need to engage with chemistry at their level, and their actual literacy skills is known as the ‘word gap’, and it is a growing problem for chemistry teachers. With 43% of year 7 students having their learning affected by a limited vocabulary, this clearly has an impact on chemistry. If students can’t understand explanations, or articulate their understanding, how can we expect them to master new conceptual ideas in chemistry?

Chemistry involves a multitude of new terms for students to learn and use. But unlike the majority of vocabulary learned in other subjects, we do not expect students to use these new terms in their everyday lives: their exposure to the language of chemistry is incredibly limited. We need to build explicit opportunities for students to develop their vocabularies so they can meet the demands of the chemistry we want them to learn.

The challenges

As the level of abstraction of a term increases, the challenge of learning and understanding that term increases as well. We can view terminology in a hierarchy:


Naming words
familiar objects, new names
new objects, new names
chemical elements
other nomenclature

Liebig condenser

Process words
capable of ostensive definition
not capable of ostensive definition


Concept words
derived empirically
with everyday and scientific meanings
theoretical constructs


As we move down this list (or up the hierarchy), we need to be aware that students will find assimilating the terminology into their vocabulary more challenging; they have less concrete experience to ‘hang’ their understanding of the term on, and find retention more difficult.

Words which are completely new to students add breadth to their vocabulary. But many terms used in chemistry have different meanings in everyday language, adding new depth of meaning to the word. When we introduce these terms, we need to ensure students understand that we want to use the term they are familiar with in a context that they are unfamiliar with.

 Terms that add breadth
Terms that add depth










A final selection of challenging words, are logical connectives: words that link ideas together and demonstrate causation. Students are usually familiar with because and however, but not with terms like consequently and conversely. This can cause problems when they are answering questions. As teachers, we tend to use the same connectives all the time, to allow students to follow the argument, but in doing so we limit their exposure to a wider range of these terms.

Teaching strategies

Making up for a vocabulary gap when students enter secondary school is a challenge we are not able to meet. But we can target vocabulary learning at the three problematic areas identified above.

The most important strategy in the classroom is for us, as subject experts, to use a wide range of vocabulary, explaining terms when students are less confident and modelling a sophisticated chemical vocabulary to our students. And then, crucially, expecting students to respond in kind, giving them time to rephrase their own ideas into the language we expect of them.

Vocabulary games make great activities though. My students enjoy untwisting my definitions and making sense of my explanations; they see them as puzzles to be solved. You can download an example of my unscrambling definitions worksheet below. Once students get the hang of these word games, they can start designing vocabulary puzzles of their own.

Chemical literacy is a challenge we need to embrace. If we don’t, students who could be great chemists, simply won’t have the vocabulary required to engage with the ideas and will give up on this marvellous subject. We need to understand the specific challenges our rich vocabulary poses to students and build explicit opportunities for vocabulary development into our teaching.

More resources

OUP offers more explanations and plenty of activities in Closing the word gap: activities for the classroom:

OUP offers more explanations and plenty of activities in Closing the word gap: activities for the classroom