Vocabulary in digital science resources for middle school learners

This corpus-based study examined the vocabulary in a 2.7-million-token corpus composed of digital science resources for middle school (6–8 grade) students in the United States. The findings of this study show that to reach the suggested 95%–98% lexical coverage thresholds of the Digital Science Corpus (DSC) that are conventionally deemed to facilitate minimal and optimal reading comprehension (Laufer, 2020), middle school (MS) students grade 6–8 must recognize the first 6,000 and 14,000 most frequent word families in the BNC/COCA (Nation, 2012), respectively, plus proper nouns and marginal words. The results of the lexical analysis across the three sub-corpora in the DSC suggest that the Life Science sub-corpora has a considerably larger vocabulary load than the Physical Science and Earth and Space Science sub-corpora. Additionally, while 98.60% of the most frequent 1,000 BNC/COCA word families occurred at least six times in the DSC, the 2,000–7,000 BNC/COCA word families provided significantly fewer opportunities for repeated occurrence. Since more than half of the words in the 5,000–7,000 BNC/COCA bands occurred five times or less in the overall corpus, most words across these bands do not have high enough frequency in the digital science resources to allow MS students to learn them incidentally from reading the texts found in digital science resources. Several pedagogically relevant suggestions for middle school science teachers are discussed.