I'm writing up my dissertation and I'm really confused where to use "the". Examples:

In this experiment, (the?) heat transfer coefficient was calculated, allowing to estimate (the?)frost thickness.


Firstly, (the?) air properties are defined.


As (the?) crystals grow in radius, the amount of air in (the?) ice is reduced, due to (the?) ice becoming more packed.

None of the nouns mentioned above have been used for the first time, so I rule out the use of "a".

Would appreciate any help.


4 Answers 4


The is appropriate in each of the places you have a question about:

In this experiment, the heat transfer coefficient was calculated, allowing to estimate the frost thickness.

Here, allowing is incorrectly used, since it needs an object (*allowing someone to estimate...*). It would be better to use something else:

In this experiment, the heat transfer coefficient was calculated in order to estimate the frost thickness.


Firstly, the air properties are defined.


As the crystals grow in radius, the amount of air in the ice is reduced, due to the ice becoming more packed.

As you said, a would not work because in each case, you're talking about a specific pre-introduced or pre-defined entity. There are times when you would want no article, but in these examples, you would want the. See the Wikipedia article:

The definite article in English is the, denoting person(s) or thing(s) already mentioned, under discussion, implied, or familiar. It is often used as the very first part of a noun phrase.

The article "the" is used with singular count nouns (the car) and with singular uncountable nouns (the coffee) and plural nouns (the cars) when both the speaker and hearer would know the identity of the thing or idea already.

However, in English, unlike in some other languages such as French, the definite article is absent before familiar but intangible concepts such as "happiness": Happiness is contagious is correct, whereas The happiness is contagious is not, unless a very specific example of happiness is referred to. The is also omitted when the noun refers to a generic mass object (Coffee grows in Colombia) or to a generic collection of countable objects (Cars have accelerators).

  • I think it might be "allowing the estimation of the frost thickness" rather than "allowing for the estimated frost thickness". These are both valid English sentences, but they mean different things. Commented Mar 27, 2012 at 21:54
  • I think you're right. Allowing isn't the best word there.
    – Daniel
    Commented Mar 27, 2012 at 22:01
  • appreciate all the comments regarding the issues with the sentences but coming back to the original question, what you're saying is that 'the' should generally be used before scientific terms. Any situations where no article is required before a scientific term? I don't really want to overly rely on 'the' or use it when it's not necessary. Example: "... to investigate how factors such as atmospheric conditions and evaporator coil geometry affect the ice build up." I reckon using 'the' before atmospheric and evaporator would just be daft, is it? any reason why?
    – Czuczu
    Commented Mar 28, 2012 at 16:53
  • See my edit and the wikipedia page. Science doesn't use more articles or fewer articles than ordinary speech. In the example in your comment above, the reason why you wouldn't use the is that "atmospheric conditions" and "evaporator coil geometry" are generic, not specific to your situation. Incidentally, however, it wouldn't sound all that wrong to use the. Thinking about the various possibilities, I'm inclined to say that there are so many intricacies in article usage that a large number of examples would be more helpful to a learner than a few rules.
    – Daniel
    Commented Mar 28, 2012 at 17:47
  • You didn't use the before factors in your comment, and you didn't ask about it, either. In fact, it would sound wrong to put the there (...to investigate how the factors...) because it's a rewording of ...such factors as... which should never have an article. Etc, etc.
    – Daniel
    Commented Mar 28, 2012 at 17:58

Daniel is right about the article use. However.

Each of the examples has another problem.

In the first example, the gerund clause ", allowing to estimate the frost thickness" is ungrammatical as it stands. Allow does not take a subjectless infinitive complement with to.

  • *Bill allowed to leave.

It should be ", allowing [somebody] to estimate the frost thickness". The identity and description of [somebody] is up to the author, but there does have to be an agent NP before the infinitive.

In the second example, notice that I didn't say "Secondly". Don't say Firstly, either.

In the third example, the final gerund clause ", due to the ice becoming more packed", with Acc subject the ice (instead of Poss subject the ice's), is an ill fit. Due to prefers a nounier object, especially a factive one.

This is a good place for a the fact that S complement, like ", due to the fact that the ice becomes more packed". Or ", due to the increasing compaction of the ice".

  • Regarding allowing, I think the context is different from what you guessed it to be. See my answer. Also, I don't think Firstly or secondly is a problem.
    – Daniel
    Commented Mar 27, 2012 at 21:47
  • +1 purely for nounier. I'd never seen it before, but 60 seconds with Google Books convinces me that in Linguistland they speak of little else! Commented Mar 27, 2012 at 21:50
  • @Daniel: I think your interpretation of allowing is unlikely/contrived. If OP wants "passive voice" he could go with "allowing for estimation of frost thickness", but even that is stilted. As John says, add an agent NP and all is fine. On the Firstly issue, I think -ly is slightly non-standard there, but sufficiently common that it's no big deal either way. Commented Mar 27, 2012 at 21:55
  • The "allowing ..." should probably be changed to "allowing for the estimation of the frost thickness". The removal of agent NPs is often viewed as desirable in scientific writing (although personally, I would disagree). Commented Mar 27, 2012 at 21:58
  • Peter: Allowing for has another meaning though, so it might get confusing. @Fumble, John: I think in order to or something similar might solve the *allowing*/agent NP issue entirely.
    – Daniel
    Commented Mar 27, 2012 at 22:06

You have to subscribe to the state of continuous presence - to imply that an object has been invisibly mentioned and whose pre-existence is inextricably required in the situation:

She heard the bell ring. She opened a window. She walked down the stairs. She opened the door.

Would you say,

She heard a bell ring. She opened a window. She walked down a flight of stairs. She opened a door.


Of course not, because it is presumed and implied the door bell is present, the flight of stairs is right there outside her bedroom, and there is one and only one a front door in most middle-class houses. But which window did she open?

Unless you are the Q of E living in many palaces with many doors and flights of stairs. I think during the time of Cromwell (am I right?), when taxes were levied on windows, and most houses had only one window, you would say, "She opened the window."

The air properties of an experiment. "The" is a determinate article. There is one and only one set of air properties from the beginning of the experiment. You would not say,

Define a set of air properties for the experiment.

That would mean conjuring any set of air properties which you would need to coerce into the experiment.

Let us write the beginning of an "interesting" novel. This is the beginning. Besides the usual preface and introduction, these are the first sentences.

I alighted from the car. I saw the ocean. The morning was beautiful. The birds were chirping. Spring has finally sprung itself from its slumber.

Has "the" car, "the" ocean, "the" morning or "the" birds been previously mentioned?

This pattern of English uses the definite article "the" to indicate to the reader to focus on the existing (implied pre-mentioned) singleton entities.

(singleton = one and only one).

Define "the" existing air properties of "the" experiment, not any irrelevant air properties from any neighbourhood.

Let's say you have been invited to a friend's house which you have never visited. On arrival, you tweeted, "I am @ G's house. The barn is gorgeous."

Would you tweet, "A barn is gorgeous"? Why not? You had never seen or even mentioned or had someone mention to you about any barn. You had not even known that the house had a barn.


This is easy to answer: Yes, use "the."

"The" is used to refer to specific things. You are referring to specific ice, a specific coefficient result, etc., so "the" is appropriate.

On the other hand, you may be making this too difficult. When describing actions or steps taken during your research, use the personal pronoun. Personal pronouns are completely acceptable in scientific and academic writing for describing what you did.

Rather than using artificial terms, such as "the researcher," or the passive voice, such as "were calculated," write in a clear, straightforward, and engaging manner using personal pronouns. A quick perusal through scientific journals will reveal that personal pronouns are acceptable.

Thus, instead of writing

In this experiment, the heat transfer coefficient was calculated, allowing [me/us] to estimate the frost thickness.

you can write

In this experiment, we/I calculated the heat transfer coefficient, which allowed us/me to estimate the frost thickness.

Note: You will want to avoid the personal pronoun for expressing opinions and other biases. For describing facts, such as what you did, personal pronouns are fine.

  • 1
    Unfortunately, the requirement in our department is to use impersonal style, otherwise it is considered unprofessional.
    – Czuczu
    Commented Mar 28, 2012 at 17:04

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