ELI5: Explain Like I'm 5

Linear isometry

Okay kiddo, so you know how when we measure something, we use a ruler or a tape measure to find out how long or wide it is?

Well, a linear isometry is kind of like a special measuring tool that helps us measure things in a special way. Instead of just telling us how long or wide something is, a linear isometry can tell us how much we need to stretch or squeeze that object so that it looks exactly the same as another object.

Let me give you an example. Imagine you have two objects, say a square and a rectangle. They might look different, but if one is just a little bit longer or wider than the other, then we might be able to use a linear isometry to make them look exactly the same.

To do this, we would first pick a point on the square and a corresponding point on the rectangle. Then we would stretch or squeeze the rectangle until those two points are the same distance apart as they are on the square. We would do this for every point on the rectangle, using the same amount of stretching or squeezing each time. When we're done, the rectangle would look exactly like the square, just a different size.

This is really useful in math because it lets us compare two things that might look different but are actually the same in a special way. We can also use it to study shapes and spaces and how they change when we stretch or squeeze them.

So there you have it, kiddo. A linear isometry is kind of like a special measuring tool that helps us compare two things and make them look exactly the same. Cool, huh?