Pupils might not be providing the answers their science teachers are looking for in exam scripts, even when these boys and girls know them.
This is because they may not have grasped the precise nature of the scientific language, and are using the wrong words.
A National Institute of Education (NIE) researcher is trying to fix this problem, which has long been a challenge in learning primary school science.
Research scientist Seah Lay Hoon started one project in 2013 and another this year to see how teachers understand students' language-related challenges in science.
The studies are funded to the tune of more than $170,000 by the Education Ministry.
Dr Seah, a former secondary school science teacher who taught chemistry from 2000 to 2002, has written two papers based on the earlier study. Her first paper on the challenges primary school pupils face in learning scientific language was published in international journal Research In Science Education in March.
The second piece, on how teachers perceive science language issues in classrooms, will soon be published in the International Journal Of Science And Mathematics Education. For the first project, which ends in July, she interviewed nine primary school science teachers and observed their lessons over six months. She also analysed written answers given in a science test by four classes of Primary 4 pupils.
Her second one, which began this year and will last until the end of next year, involves in-depth interviews with five secondary school teachers and planning lessons with them.
Her initial observations are that teachers tend to focus on content and neglect language, due to constraints such as time in the classroom.
Teachers do not always convey to students "how language in science has distinctive features, and is different from everyday English", she said.
For instance, a balloon "inflating" or "expanding" may project the same image of a balloon becoming bigger, she said. "But inflating gives you a more precise meaning because you know that something is entering the balloon, so that it expands."
She is now developing lesson strategies with teachers to help students learn science better.
These include helping students to identify scientific concepts such as "cause and effect" or "compare and contrast".
Other ways include getting "wrong" answers from students through games at the start of lessons before teaching them the right ones, so that they understand why the right answers are better.
This could help students tackle open-ended questions better, said Dr Seah.
Manu Kapur, who is head of research at NIE's Learning Sciences Lab agreed, saying: "If you go prematurely into teaching keywords, that's not good. Kids don't learn well if they're just told 'you cannot use this term or that term'."
The issue of precise language in science was raised when several parents wrote to The Straits Times' Forum page in February.
They said their children had been unduly penalised for answers that had the same meaning as the correct ones, but did not contain the right "keywords".
Dr Seah acknowledged that some teachers may be stricter than others in marking, but stressed that scientific language demands precision.
When asked how a lion was different from a bird, for instance, stating that "a bird has feathers but a lion does not" may not be enough as students need to compare both animals' outer coverings, she noted, and the better answer would be "a bird has feathers but a lion has fur".
Elizabeth Tan, whose son is in Primary 6, said the studies will be useful in helping teachers understand how students think. "But in reality, teachers are under pressure to finish content and make students score better, so the easiest way is to teach keywords," said the 41-year-old housewife.
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