How to Use Tenses within Scientific Writing

One’s tense will vary depending on what one is trying to convey within their paper or section of their paper. For example, the tense may change between the methods section and the discussion section.

Abstract --> Past tense

• The abstract is usually in the past tense due to it showing what has already been studied.

Example: “This study was conducted at the Iyarina Field School, and within the indigenous Waorani community within Yasuni National Park region.”

Introduction --> Present tense

• The introduction is usually in present tense due to the fact that you are presenting facts and background information on your research topic. By having this information in present tense, you are showing that you believe that this research is correct. Present tense should still be used even if the research you are speaking of aged.
  • Example: “ Clidemia heterophylla and Piperaceae musteum are both plants with ant domata, meaning that there is an ant mutualism which protects them from a higher level of herbivory.”

  Methods --> Past tense

  • In the methods section one would use past tense due to what they have done was in the past.
  • It has been debated whether one should use active or passive voice. The scientific journal Nature states that one should use active voice as to convey the concepts more directly.
  • It can be beneficial to use passive when one wants to keep a similar subject in a series of sentences within a paragraph. Passive voice also allows one to help move words to emphasize them. Passive voice can also be useful when emphasizing the action but not the one doing the action.
    • Example: “In the geographic areas selected for the study, ten random focal plants were selected as points for the study.”

    Results --> Past tense

    • Past tense would typically be used due to these results being found in the past
      • Example: “We observed that there was no significant statistical difference in herbivory on Piperaceae between the two locations, Yasuni National Park, Ecuador (01° 10’ 11, 13”S and 77° 10’ 01. 47 NW) and Iyarina Field School, Ecuador (01° 02’ 35.2” S and 77° 43’ 02. 45” W), with the one exception being that there was found to be a statistical significance in the number count within a one-meter radius of Piperaceae musteum (Piperaceae).”

      Discussion --> Present tense and past tense

      • One would use present tense if they are explaining why one cares about their results and why they are important
        • Example: “Symbiotic ant mutualistic relationships within species will defend their host plant since the plant provides them with food. In the case of Melastomataceae, they have swellings at the base of their petioles that house the ants and aid to protect them from herbivores.”
        
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