• iceberg
  • boy with flowers
  • checking water quality
  • planet eclipse
  • solarsystem model
  • rangitoto trees
  • kids with test tubes
  • kids with earth
  • snowy mountains
  • teens in physics class
  • Rainbow Clouds

    Refraction and diffraction of light through ice crystals in the clouds

  • Philippa On The Ice

    Philippa On The Ice Philippa Werry at an Antarctic research camp 2016

New Zealand Science Teacher

Science Curriculum/Scientific Literacy

Teaching causal text connectives in chemistry

A Yr 12 Chem class struggled writing long answers to NCEA Chemistry questions because they didn’t understand causal text connectives. A literacy intervention changed classroom practice for better NCEA scores, as David Whitehead, Waikato Uni, and Fiona Murphy, Sacred Heart Girls’ College Hamilton explain:

The challenge: long-answer format questions

Since the advent of long-answer format questions in the 2008 National Certificate of Educational Achievement1 (NCEA) Chemistry examination, students have faced and failed the literacy challenge posed by the new format. Coinciding with the advent of long-answer science questions, Fiona, a teacher of Year 12 Chemistry, noticed a decrease in students’ ‘Excellence’ grades, and an increase in ‘Standards Not Attempted’. More specifically, as the 2007-2008 data indicate (see Table 1), she had noticed an increase in the percentage of students ‘Not Achieving’ in Atomic, Reactivity and Redox topics, a decrease in ‘Merits’ achieved in two of those topics, and a marked reduction in ‘Excellences’. Investigation of these results indicated that students did not attempt standards because of a lack of time, rather than a lack of knowledge. In short, it appeared they were not skilled enough to write connected text answers quickly.



 Table 1: NCEA results from three, Year 12, mixed ability classes in one school by topic 2007-2008

 Year Topic  Not achieved (%)  Achieved (%)  Merit (%)  Excellence (%)
 2007 Atomic 11.4 36.4 38.6 13.6
 2008 Atomic 21.9 43.8 32.8 1.6
 2007  Reactivity 16.7 61.9 19.0 2.4
 2008  Reactivity 22.4 55.2 22.4 0.0
2007 Redox 14.0 41.9 32.6 11.6
2008 Redox 25.9 46.6 22.4 5.2


The NCEA is New Zealand’s national achievement standards-based qualification at four levels (not achieved, achieved, merit and excellence), and operates in the last three years of high school. Achievement standards are assessed internally or externally through end-of-year examinations and are constructed based on generic marking criteria.

These suspicions were confirmed by the 2008 NCEA Chemistry examiner’s report that stated the most common problem among students attempting long-answer questions was that they wrote in statement form. This form had been appropriate for short-answer questions in previous years, but it was inappropriate for the new long-answer question format.

Nationally, chemistry teachers were now faced with the added responsibility of helping their students write more cogently. Locally, Fiona was determined to meet this new challenge with her Year 12 chemistry classes, but to do so she needed to establish exactly why her chemistry students found writing connected text challenging.

Fiona discovered, by answering NCEA questions herself and studying exemplars, that demonstrating an understanding of the science underpinning chemical reactions, and of the chemical reactions themselves, was dependent on an ability to compose justifications. Further, the secret to writing these justifications lay in the use of causal text connectives such as ‘because’ and ‘however’.


Showing cause/result

Indicating time

in other words so then
in other words therefore next
that is consequently finally
namely due to..., owing to meanwhile
in fact because of this previously

Sequencing ideas

Adding information


firstly, first, second, third... too in that case
at this point in addition however
to conclude also despite this
given the above points again even so
to get back to the point similarly if not


Figure 1: Text connectives (Ref: Derewianka, 2005).


Text connectives assist writers to compose appropriate relationships among (scientific) ideas. Derewianka (2002) suggests they serve as ‘signposts’, and are as essential in the composition of chemistry explanations as they are in the composition of narrative (Meyers, Shinjo, & Duffy, 1987). Figure 1 lists a range of text connectives of which Fiona’s Y12 chemistry students needed those showing cause/result.

To confirm her initial hunch, Fiona collected baseline data from students in the form of written responses to a long-answer Y12 chemistry examination question that was based on content taught during Year 11. Answers were analysed around three criteria: (i) the use of key content words; (ii) the use of definitions; and (iii) the construction of justifications, which required the use of causal text connectives.

It was evident from an analysis of this data that students could use key content words to compose factual statements, but could not link these with causal text connectives. Without the use of these connectives students were limited to ‘Achieved’ grades.

Together, results from an analysis of baseline data, and the knowledge that the next NCEA chemistry examination would include long-answer type questions, engendered a sense of urgency around teaching students how to use causal text connectors. Success was by no means certain. However, Fiona hypothesised that teaching connectors to one class, might help them make explicit understandings of the casual inferences associated with, for example, formula representing chemical reactions and scientific explanations of why those reactions occurred. Additionally, the construction of long answers that used these connectives would, Fiona assumed, make clearer to examiners whether her students understood the science.

Teaching causal connectors

1. The teacher

Fiona has taught science for 13 years and admits to being a teacher of chemistry first, not a teacher of writing. Nevertheless, she was knowledgeable, and increasingly so, about the literacy demands of her subject, and the literacy needs of her chemistry students. This was especially the case in regard to their ability to answer long-answer examination questions, which she believed had become as much an exercise in writing as they were a test of scientific knowledge.

Fiona was clear that it was no longer acceptable for teachers of science to use the adage that the teaching of writing should be left to English teachers. Rather, she believed students of science needed to be taught how to write science. Fiona was motivated by a desire to see her students succeed, determined that the literacy requirements of Year 12 chemistry did not create an extra burden on her students, or herself, and keen that teaching writing was seamlessly integrated into the class routine.

2. The students

The research was conducted in a decile 7, urban, girls’ school, with a roll of 880 students. The school’s NCEA pass rate is one of the highest in the area, especially at Levels 2 and 3. The students in the three research classes were sixteen or seventeen years old. To enter the Year 12 chemistry course students needed to pass two out of four Year 11 NCEA science external examinations, including a chemistry paper. There was a similar distribution of above ability English students in each of the three research classes. The classes were equivalent, because they had similar Year 11, Level 1, NCEA science profiles, and because the majority of students in each class were studying for the Cambridge English examination, or were in the upper ability English classes.

3. The plan

The goal was to help students construct long answers to chemistry examination questions. To achieve this, Fiona planned a year-long programme designed to teach causal text connectives. She selected three mixed ability Year 12 chemistry classes: Class 1: ‘literacy intervention’ class of 22 students, and taught by Fiona; Class 2: ‘control’ class of 21 students, and taught by Fiona; and Class 3: ‘neutral’ class of 23 students, and taught by another teacher.

4. The process

Fiona discussed with the students her proposal to conduct research as part of her teaching. The research design included semi-structured interviews, observations and written feedback from students to describe the effect of the embedded literacy intervention. The general question: “What effect is the ‘language focus’ having on your writing?” was used during interviews with both individuals and small groups of students. Subsidiary questions used were:

  1. How did you find the concentration on writing during the Chemistry topics?
  2. Do you feel more comfortable attempting the examination questions? Please explain your answer.
  3. Now that you have this knowledge about writing, how would you approach an examination question?

Observations of students during each class were recorded in a reflective diary. More formal written feedback was obtained each school term when students were asked to write a response to the general question: “What effect is the ‘language focus’ having on your writing?” NCEA data from the three Year 12 classes were compared descriptively.

5. The teaching procedures

At the beginning of the year, before any chemistry teaching commenced, the class discussed the use of text connectives. Fiona demonstrated on the white board how the two sentences: ‘Sodium chloride is an ionic compound. It has positive and negative ions.’ can become a justification with the use of a causal text connective: ‘Sodium chloride is an ionic compound because it contains positive and negative ions.’

Fiona’s class was then introduced to other text connectives that can be used when composing long-answer chemistry questions (see Figure 1 cause/results words). Subsequent lessons involved students constructing further justifications from two sentences by using the connectives.


The Lewis structures of two molecules, NH3 and COCl2, are shown below.

Base question: Discuss the polarity of these molecules.









Use the following statements and justifi cations to answer the question above. Do not forget every statement needs to be linked to a justification.

  • NH3 is a polar molecule
  • COCl2 is also a polar molecule
  • 4 areas of electron repulsion around the central atom
  • 3 areas of electron repulsion around the central atom
  • 3 bonding and one non-bonding
  • All areas are bonded
  • Shape is trigonal planar
  • Shape is trigonal pyramid
  • Bonds are polar
  • Difference in electronegativity
  • Bonds are asymmetrical
  • Effect of them is not cancelled.


Figure 2: Example of an activity using Starter Statements (adapted from 2008 Atomic and Bonding examination).


Cloze exercises were also used to teach the use of text connectives. Students were already familiar with the use of cloze exercises to teach key vocabulary. In the present context, Fiona designed cloze passages that included justifications and deleted the causal text connectives to construct the cloze exercise. A list of causal text connectives was listed below the cloze. Additionally, students were given a question with a list of statements and justifications. Their task was to align the statements and matching justifications, and link them with an appropriate text connective (see Figure 2). For example, students used the bulleted statements listed in Figure 2 to help them develop their justifications. After they had written their answers, students highlighted the causal text connectives. As the students became familiar with the activity, it was made more complex by Fiona providing statements and the students composing links and justifications.

Another activity designed to highlight the role of causal text connectives involved students responding to long-answer questions individually, and then revising these answers as a group. Students then looked at other groups’ work to identify if they needed to add anything to their own answer. Next, they highlighted statements, causal text connectives and justifications using different coloured pens. Finally, the teacher’s model answer was provided and students used this to further review their own work. Initially, students needed direction on how to review their examination answers and move from a position that their work was “right” or “wrong”, to focus on their strengths, and identifying areas for further development.

      Table 3: NCEA 2010 results for Year 12 mixed ability class, by class and topic

 Year/topic  Not achieved (%)  Achieved (%)  Merit (%)  Excellence (%)  SNA (%)
Class 1 (literacy intervention)  18 41  28  14 
Class 2 (control)  19 48  29 
Class 3 (netural)  30 39  26 
Class 1 (literacy intervention) 5 18  32  18  27 
Class 2 (control) 14 24  24  36 
Class 3 (netural) 35 35  13  13 
Class 1 (literacy intervention) 27 14  32  23 
Class 2 (control) 19 38  14  - 29 
Class 3 (netural) 35 39 13 - 13


1. NCEA test results

NCEA test results provided one comparative measure of whether the literacy intervention was associated with improved student achievement. Table 3 indicates the 2010 NCEA results by topic for the three ‘mixed ability classes involved in Fiona’s research. The most notable result is the percentage of ‘Excellence’ grades achieved by the ‘literacy intervention’ class across all the three topics. Another notable feature is the success of the ‘literacy intervention’ class at the ‘Merit’ pass level, especially with the Reactivity and Redox topics. In contrast, Class 3, the ‘neutral’ class, had the largest percentage of ‘Not Achieved’ and ‘Achieved’ grades of all three classes.

2. Student feedback

Student feedback provided a second measure of change associated with the literacy intervention. At the beginning of the literacy intervention, students had stated that connectives were important in English, but not in chemistry. After demonstrating the role of causal text connectives when composing science justifications, the students started to understand that connectives were just as important in chemistry.

At the end of each unit, literacy intervention class students answered the question: “What effect is the ‘language focus’ having on your writing?” Students responded that the language focus was “useful” and that they “could see why literacy was important”. They also indicated that they would like other subjects to concentrate on writing.

These students felt unanimously “more comfortable” to attempt the examination questions, because they knew how to structure their justifications. They also realised the importance of definitions, and their role as “answer starters”. Students also identified the need to back-up every statement with a reason and to back the reason with the science. An indicator of this understanding emerged during the literacy intervention group’s examination preparation.

The class created the following framework: “Statement à Justification à The science”.

For example:

Statement: NaCl is an ionic compound

Justification: Because it contains sodium ions and chloride ions held in a 3D lattice 

The science: Ionic compounds form strong electrostatic forces due to the transfer of electrons. The sodium ion (cation) will lose an electron, which will be gained by the chloride ion (anion). Consequently ionic compounds have the following properties...


Fiona’s literacy intervention was prompted by changes to the 2008 NCEA examination that required students to write long answers. Examination data from 2007 to 2010 indicated that the change from short-answer to long-answer questions had challenged students who were, nevertheless, confident with the content of their chemistry programme. Baseline data indicated that Fiona’s class was less confident writing cohesive answers in the form of connected text. This initial finding suggested students were unable to transfer their understanding of text connectives from their English classes, as much as it indicated the demands of chemistry as a unique discourse.

What the research indicates is the importance of baseline data, of knowing students’ needs, of engaging in research-based teaching and of appropriate pedagogical content knowledge. In respect to the latter, Fiona was able to select and apply a range of appropriate and effective literacy strategies designed to improve students’ writing, and more specifically, assist her students to better structure their understanding of chemistry concepts.

Positive changes to the examination, coupled with responsive changes to how Fiona taught enabled her students to acquire the discourse of science, which in turn gave them access to the world of chemistry. In short, Fiona was able to scaffold her students into the way scientists write, think and create their reality. By adopting the mantra of “every teacher a teacher of literacy” Fiona’s intervention empowered her students; an empowerment that was ultimately socially signified by high levels of ‘Merit’ and ‘Excellence’ passes in a national high-stakes examination.  

For further information contact davidw@waikato.ac.nz

1 The NCEA is New Zealand’s national achievement standards-based qualification at four levels (not achieved, achieved, merit and excellence), and operates in the last three years of high school. Achievement standards are assessed internally or externally through end-of-year examinations and are constructed based on generic marking criteria. 


  • Derewianka, B. (2002). A grammar companion. Newtown, NSW: Primary English Teaching Association.
  • Derewianka, B. (2005). A functional model of language. North Sydney: Board of Studies, New South Wales.
  • Myers, J.L., Shinjo, M., & Duffy, S.A. (1987). Degree of causal relatedness and memory. Journal of Memory and Language, 26, 453-465.

Post your comment


  • Hi Rebecca, thanks for your comment! I apologise for the missing tables, we are working on them and they should appear by tomorrow lunchtime so please check back then.

    Posted by NZ Science Teacher, 23/07/2013 3:14pm (8 years ago)

  • I have been looking at Literacy for Senior Chemistry this year and it is great to find some research on it and to see just how much of an effect it can have.
    I however can't see the figures and tables - is there anyway to access them?

    Posted by Rebecca, 23/07/2013 2:51pm (8 years ago)

RSS feed for comments on this page | RSS feed for all comments