Clockwise vs counterclockwise
Gradually, you can introduce the concept of half turns and quarter turns by showing them inverted images.
Parents can participate in fun learning activities with their toddlers to help them identify various movements and differentiate CCW from CW. Now that you have learned about CCW motion, note down a list of other daily chores that involve such motions and identify whether they are CW or CCW. Step 3: Repeat this motion and observe the movement of your finger. Step 2: Create an imaginary C in the air. Let us perform a small activity together. The alphabet C is an easy example to demonstrate counterclockwise motion to young learners. Turning off taps, turning a key in a lock to secure it, and unscrewing a screw, are some examples of CCW motion. We perform several activities throughout the day without realizing that they involve CCW motion. Examples of Clockwise and Counterclockwise MotionĮveryday examples are a great way to teach young children. Ensure that kids observe the movement of the clock hands and instruct them about clockwise and counterclockwise motions. Let us look at the picture below to understand these movements better.Ī sound understanding of motions (both CW and CCW) helps express directions clearly and understand instructions. But you may be wondering which way is counterclockwise? Subsequently, the circular motion towards the left is counterclockwise or anticlockwise, often denoted as CCW and ACW, respectively. Thus, any rightward motion in a circular fashion is known as clockwise, often denoted as CW. Things like the movement of the clock hands are towards the right. Understanding movements is essential for young learners to grasp the workings of a clock and subsequently tell the time. To help children master the knowledge about directions, we need to start early. Examples of Clockwise and Counterclockwise Motion.So for the inventors of trigonometry there was probably no choice but to count argument counterclockwise. Of course I understand that these are not original pictures, but it is hard to imagine that the original pictures looked differently. Choosing the other direction in trigonometry as positive would be extremely inconvenient for the main purpose of it.ĮDIT All pictures illustrating Ptolemy are made with Sun, Moon and planets movingĬounterclockwise (as they actually move with respect to the fixed stars, as seen from the Northern hemisphere). In particular trigonometry was invented and developed for the needs of astronomy. So positive direction is counter-clockwise.Īs mathematics was always closely connected to astronomy (well, until 20s century), it was natural for mathematicians to take the same direction of rotation as positive. (Planets sometimes "retrograde" but they retrograde with respect to this positive, natural direction). As all they move generally in the same direction (opposite to the direction of the daily rotation), this direction was traditionally called "positive" or "forward" in astronomy. However interesting astronomy begins when you start to appreciate and describe the slower motions than the daily rotation: the progress of the planets, Sun and Moon with respect to the "fixed" stars. This determines the clockwise direction, as the time was always measured by the Sun. If you observe from Northern hemisphere, the sky rotates about you clockwise (East to West). It so happened that in the ancient times astronomy was mostly practiced in the Northern hemisphere. I suppose that all these notions and terminology come from the early astronomy.
(Although I've wondered this a long time, this posting was triggeredīy the MESE posting, " Why do we conventionally treat trig functions as going anti-clockwise from the right?.")
Likely the answer to Q2 depends on nationality/culture. Are there data on how we mentally view the annual calendar advancing-linearly: L/R, R/L, circularly: cw, ccw? Where did the mathematician's ccw convention originate, and where did the clockwise convention originate, and why are they opposite one another? I learned when making a presentation to random people (faculty) that many (most?) view the annual I myself, as a mathematician, view the annual calendar as advancingĬcw-summer South, fall East, Christmas North-but On the other hand, non-mathematicians are exposed to cw advancement as increasing time in all(?) analog clocks,Īnd so for many of them, cw is the natural sense of positive angular advance. The right-hand-rule rules such coordinate systems.
To $90^\circ$ along the positive $y$-axis (North), sweeping out the first (NE) quadrant of It is common for mathematicians to use counterclockwise (ccw) as positive, andįor example, trigonometric functions increase from $0^\circ$ along the positive $x$-axis (East)