ELI5: Explain Like I'm 5

Parametrization by arc length

Parametrization by arc length is a fancy way of describing how to draw a curve in a way that makes it easier to measure and talk about. Imagine drawing a wiggly line on a piece of paper. If you want to figure out how long the line is, you would have to use a ruler and measure each little segment of the line. But if you draw the line in a special way called parametrization by arc length, you don't need to use a ruler anymore!

When we parametrize a curve by arc length, we create a formula that tells us where the curve is located at every point along its length. This formula is based on something called the arc length, which is just a fancy way of measuring the length of a curve. If we know the arc length, we can use it to figure out exactly where on the curve we are - kind of like a map that tells us where we are in the world.

So, how do we parametrize a curve by arc length? First, we need to pick a starting point on the curve (let's call it point A). Then we use some fancy math to figure out how far away each point on the curve is from point A in terms of arc length. This gives us a series of numbers that we can use as inputs for our formula. For example, if we want to know where the curve is when we've traveled 3 units along its length, we can plug in 3 to our formula and it will tell us exactly where we should be.

Overall, parametrization by arc length might seem complex, but it's really just a way of simplifying the process of measuring curves. By creating a formula that tells us where the curve is based on how much of it we've traveled, we can quickly and easily measure and study curves without the need for complicated measurements or calculations.