## The perspective on “clockwise”

With a blog with the name “tymshft,” it makes sense to consider how time is communicated.

At this point, some of you are looking at me and shaking your head. “You just check it on your phone, stupid!”

Some people realize that I’m talking about clocks – you know, those things that show you three or four numbers that tell you what time it is.

However, some people – not all of you – realize that I’m thinking about something completely different. While the thing that I’m thinking about was called a “clock,” it would never display a time such as “12:35” or “1:47.” In fact, although this clock had numbers on it, no number was greater than 12. (For the moment I’ll ignore clocks with “numbers” such as XII – I realize that some heads are spinning already.)

So how could a clock display the proper time if it didn’t have any numbers greater than 12?

Now I suspect that my older readers are looking at me and shaking their heads. “You just look at the hands, stupid!”

But how do you explain clock hands to someone who has never seen them? I will attempt to do so in the next two paragraphs.

Imagine a circle in which the numbers 1 through 12 are arranged around the circumference of the circle. Now imagine that there are two sticks that point out from the center of the circle – a short stick and a long stick. These are called “hands.” (Don’t ask me why.) Let’s start by looking at the short “hand.” This represents the hour. If it’s pointing at the number 12, then it’s 12:00. If it’s pointing at the number 1, then it’s 1:00. If it’s between the 12 and the 1, then we have to look at the long “hand.” This represents the minute. Let’s take a deep breath, because this is where the math comes in. When using the minute hand, everything has to be multipled by five. If the minute hand is pointing at the 1, then it’s five minutes after the hour. If the minute hand is pointing at the 9, then it’s forty-five minutes after the hour. But if the minute hand is pointing at the 12, then it’s zero minutes after the hour.

So what does this mean? This means that if your clock says “12:00,” the older clock would have the hour hand (again, the short hand) pointing at the 12, and the minute hand also pointing at the 12. If your clock says “12:05,” then the older clock’s hour hand points at the 12, and the minute hand points at the 1. If your clock says “12:42,” then the hour hand is between the 12 and the 1, and the minute hand is between the 8 and the 9.

For those of us who grew up with this time-telling system, it’s pretty intuitive. But if you’ve never seen a clock with hands before, the whole time-telling thing could baffle you for days, or weeks, or months.

But that’s not what I wanted to talk about.

On these older clocks, both the hour and the minute hand move around the circumference of the circle in a particular direction. And they always move in that direction, never reversing themselves to go in the other direction. That direction, naturally, is referred to as “clockwise.” And if you’ve never seen a clock, I haven’t the slightest idea of how to explain “clockwise” to you.

Now if you consider the opposite direction – in other words, moving around the circumference of the circle in the opposite direction from the clock hands – that direction is called “counter-clockwise.”

Once you understand the workings of a clock with hands, the “clockwise” and “counter-clockwise” directions are extremely easy to comprehend. You can use them at will to describe a number of things:

*When you enter the building, you’ll be entering on the southwest corner. If you go clockwise in the main hall that circles the building, you’ll reach the Learning Center meeting room. I’ll be in there.*

Ah yes, perfectly understandable – if you live in two dimensions.

Unfortunately, we live in three dimensions (except for Professor Nick Wheeler, who lives in seventeen dimensions).

To understand the problem, imagine a glass clock in the center of the hall. Look straight at the clock, and watch the clock hands move. They are moving clockwise.

Now go behind the glass clock and look at the hands.

In which direction are the hands moving?

Let me teach you something we learn in engineering: the right hand rule. Make a loose fist with your right hand, point the thumb up, and look down the thumb. Your fingers curl “counter-clockwise”. A lot of scientific conventions use the right hand rule, such as the direction of magnetic flux around a current-carrying conductor, the threads on a screw, or the positive angles on a polar graph. Clocks are one of the few things that go against the right-hand convention (unless you’re viewing from behind the face).

Thanks for sharing the right hand rule. But since I’m left handed, wouldn’t my left hand be right?