Recently there has been an increasing need to master and accept English as an international language. The field of science had not been an exception as there has been a growing interest on the part of university professors and students to access or to write and to publish scientific articles in English. This imposes a great demand on English for Specific Purpose (ESP) and English for Academic Purpose (EAP) teachers to develop materials that are in line with the specific needs of different people in different fields or various branches of science.
Considering the importance of vocabulary in language learning and especially in an academic setting, a very critical point to decide in advance is which vocabularies are worth teaching in the limited hours of class time. (Cohen, Glasman, Rosenbaum- Cohen, Ferrara, & Fine, 1988) state that academic vocabulary may trigger serious difficulties and problems for language learners since they are not familiar with academic words as they are with the technical vocabularies of their own field of study, nor as with general service vocabulary items which have high frequency of occurrence (see also Worthington & Nation, 1996; Xue & Nation, 1984).
While the corpus of previous academic wordlist was a combination of texts from different majors, the sub-corpora were not of a considerable amount. On the other hand, the previous corpus used large bodies of text, i.e. books that may in some way represent certain editors or writers‟ preferred way of writing which in some ways may lead to some bias in the corpus. In the present paper the researchers tried to include more words in the corpus for the fields of science and to include short materials in corpus in contrast to corpus of previous studies.
The present study aims to answer the following questions:
1. What percentage of the words in the Hard Sciences Corpus does the AWL cover?
2. What percentage of the words in the Hard Sciences Corpus does the GSL cover?