Physics of Media Arts: Conceptual Physics for Students of the Media Arts

In order to explore physics, we need to work with numbers and units. So before we launch into physics, we have to spend a little bit of time understanding what those things are.

Here is a seemingly simple question: What is the number three? Yes, you can draw the arabic numeral 3 and say that this is 3. But that doesn’t really get at the question, since there are lots of ways to write the number 3. We can also write three using a system of tally marks, or using numbers from a different language. Your next impulse might be to try gather three objects and say that these objects represent the number three. But is that true? How would we know from this that if we grabbed three other objects that those other things would also be three?

It turns out that the question of "What is a number?" is extremely complicated and can lead down rich paths of mathematical philosophy. For example, we can think about numbers in terms of their properties (numbers behave like this) or we can try to think about the "essence" of numbers (what makes a number a number and not something else?). And as you get deeper into the subject, you’ll find that there is not a single simple answer to the question. (This is another example of how simple questions can lead to complicated answers.)

For our purposes, we will stick with the idea that numbers are symbols that represent a quantity or an amount. You might ask, "A quantity or amount of what?" And that’s a good question to ask. Numbers don’t tell us that. They just represent the abstract concept of quantity or amount. In order to know what sorts of things we have quantities of, we have to add a unit.

A unit is a word that represents a known quantity that represents a standard for a measurement. In casual contexts, the known quantity can be something simple like an apple. It makes sense for us to say that there are "five apples" on the table. However, from a more scientific perspective, an "apple" is not precise enough for us to use for our studies. What type of apples are they? And even if we have the same variety of apple (say, red delicious apples), they can be of many different weights and sizes. This makes for a very imprecise form of measurement.

When it comes to science, we have to use very precise quantities to avoid this type of variation. This will be the topic of the next section.