Have you noticed that some areas of knowledge seem to have their own language? A specialized area of knowledge and skills is called a subject domain. For example, the subject domain of meteorology includes the scientific study and forecasting of weather. Meteorology, like many other subject domains, has its own collection of technical terms. Just as important, it uses some everyday words in special ways.

Which words in this diagram are ones that you might use in everyday conversations about your life―but have different meanings when used to describe a scientific event?

Identifying the domain in which a word is used can help you understand its intended meaning in a text. You can extend your knowledge even further by taking a close look at the word’s parts―its root, prefixes, and suffixes.

Several of the words in this paragraph from “Thunder and Enlightenment” belong to a subject domain. See if you can guess which ones. Then, click the paragraph to check you answer.

I realized Ram's question came from something that had taken place in class a few weeks earlier. We were studying a science unit on weather, concentrating on thunder and lightning. The text gave a rather complicated explanation that involved atmospheric temperature gradients, rising air masses, ionic exchanges, positive and negative electric discharges, and the speed of light versus the speed of sound. Pretty heavy stuff for these young boys and girls who live far from roads and electricity!

I realized Ram's question came from something that had taken place in class a few weeks earlier. We were studying a science unit on weather, concentrating on thunder and lightning. The text gave a rather complicated explanation that involved atmospheric temperature gradients, rising air masses, ionic exchanges, positive and negative electric discharges, and the speed of light versus the speed of sound. Pretty heavy stuff for these young boys and girls who live far from roads and electricity!

The “pretty heavy stuff” that the author refers to is the use of special terms and concepts in the subject domain of meteorology. Atmospheric is related to the word atmosphere, the layer of gases surrounding a planet. It is used to refer to anything between the earth and outer space. Gradients are slopes or inclines. In the context of meteorology, though, they are the rates at which the temperature changes in response to variables such as height and distance.

The paragraph contains several words that have both general and domain-specific meanings. See if your knowledge of weather science will help you identify the meaning they have in “Thunder and Enlightenment.” Click each word when you have a good guess about its scientific meaning.

positive

In scientific subject domains, positive describes atoms that have more protons than electrons.

negative

In scientific subject domains, negative describes atoms that have more electrons than protons.

discharges

As a general science term, a discharge is the flow of positive or negative charges (protons or electrons) to a different area. In meteorology, lightning is a considered a discharge.