Paragraphs: Topics Sentences

Within language studies there are a wide number of definitions for 'topic sentence'. This creates quite a lot of confusion among students. Here, we will utilise our own, straight-forward, definition, and simply define a topic sentence as: "The first sentence of any academic paragraph".

Indeed, within academic writing, there a typically three ways to begin a paragraph:

1. Introductory Topic Sentence

Definition: The writer provides factual background or contextual information

  • Natural Science Example: “Heat transfer can occur by radiation, convection, or conduction and is measured in units of joules (J).”
  • Humanities Example: “The tension between the responsibility and unlimited power has been part of a longstanding debate in certain legal systems, namely, the Anglo-Saxon one.”

2. Transitional Topic Sentence

Definition: The writer signals to the reader that they are changing from one broad topic to another within the document.

  • Natural Science Example: “Besides the problem of corrosion, there is another significant problem that should be considered.”
  • Humanities Example: “Having considered the issue of constitutional legality and the 'unwritten constitution', let us look at its relevance to the legal system.”

3. Thesis Topic Sentence

Definition: The topic sentence and the paragraph's claim is combined into one. You could also see it as a paragraph with no introductory sentence but, rather, one that goes directly into the paragraph's claim. This concise approach of course allows for more support sentences.

  • Natural Science Example (Claim): The different types of mosaicism observed in in vitro embryo cultures for ART procedures leads to two different classifications: cell occurrence and cell complement.
  • Natural Science Example (Statement of Result): Figure 5.17 shows the measured magnetic field intensity (By) over the course of the experiment for both a single jet (a) and the collision of two turbulent jets (b).
  • Social Science Example: The opportunities provided by the adaptation process have stimulated farmers to learn from one another’s approaches and develop their own adaptation strategies.