Density can be a confusing subject. Normally density refers to how much of something is packed into a given space. That seems simple, but people often get confused. Or maybe it's just me.

I think the reason for the confusion is that scientists sometimes use words differently than non-scientists. The scientific use of the word is the correct one, of course. But people sometimes use scientific terms as if they were analogies, similes, metaphors, parallels, similitudes, equivalencies, or homologies.

None of these latter terms are scientific terms, although as I recall from my English classes, they do have very specific definitions which I never could remember. It didn't help that my English teacher thought I was dense. I mean, in High School I was 6-foot-1 and weighed 105 pounds. There is no way in the world that could be called dense! Having lost a couple of inches and gained several pounds, I am far denser today than I ever was in high school. My wife even thinks so. I asked if she thought I was more dense now than in high school and she said, "For sure."

The problem with using density as an analogy, simile, metaphor, parallel, similitude, equivalency, homology, or whatever, is that scientifically, density refers to the fact that big things are made of little things. Most very-big, complicated things are made of a small number of little things that are connected to one another. For example, buildings are made of the same short list of components. Vehicles have a list of common elements that are generally standardized. Molecules are made of a few atoms. Atoms are made of some other little things — which are made of other little things ...

Once these little things become connected, they take up three-dimensional space. We call the occupied space volume. But any given volume can contain a variable number of little pieces. If there are a lot of pieces jammed into the volume, we say that it is dense. If there are fewer little pieces, we say the object is less dense.

Now do you see why we shouldn't use the word dense as an analogy? There is no accurate way to tell how many non-scientific imaginary pieces are packed into the space of a human body. Some parts of the body might even be dense while other parts are less dense.

But there is an even bigger problem. Some people refer to others who are slow in picking up on social cues as being "dense". Well, just how many social cues are there? I apparently don't know very many.

Then we turn around and use the word dense to describe people who don't seem able to remember the difference between metaphors and similes. Wouldn't that be a lack of something, not understanding metaphors and similes? How could having less of something be dense?

I've even heard the word dense applied to scientists and engineers when it comes to romance. Dense things cannot have less of something than "undense" things. Besides, men in general, don't understand romance, so does that make all men dense? Okay, don't answer that.

I guess it makes sense to say that a dense brain is full of a lot of neurons. But I don't see what that has to do with recognizing social cues, language definitions, or romantic sensitivities. Shouldn't a dense brain have more room for facts and less room for metaphors?

Being dense is somehow supposed to be a bad thing unless you are a linebacker. But I don't understand what exactly the supposed advantage is of having a less-dense brain. I admit that I found myself with other things on my mind than metaphors. In fact, I had so much on my mind that there just wasn't room for similes. My English teacher should have called me "undense."

Seems like an English teacher using the wrong adjective to describe a student is a little dense.

Gary McCallister, gmccallister@bresnan.net, is a professor emeritus of biological sciences at Colorado Mesa University.