 When we start worrying about directions of things again, we'll notice that distance doesn't have a direction. Distance is a scalar quantity, whereas displacement does care about direction. If I'm there, that is a different displacement to there. And so displacement has direction. And when we're just on a line, it can only be positive or negative, but that means it's a vector quantity. We can talk more about how to deal with vectors that aren't all in one line later. Now, if we wanna talk about something moving around in time, a good way to describe that is with a graph. And so if we have a graph of position as a function of time, then if they're not moving at all, they'll stay at the same position. And if they are moving, this will have a slope. And if they change the slope, that means they're gonna change their velocity. And it turns out that in physics, we make a distinction between speed and velocity. And it's exactly the same distinction we're making up here. So the speed is just the total distance traveled divided by the time taken. And so that's a scalar property, just like distance was a scalar property. So if you jump on a car and you go onto the highway and go as fast as you can to the nearest city, then you turn around and come almost all the way back again, then your speed can be extremely high because you traveled a very large distance in a fairly short time. But your displacement was quite small because you ended up almost back where you started from. And so that means your velocity is low. So velocity is a vector because it's got a direction. So if you travel backwards, then you have a negative velocity. So the velocity here would be zero. The velocity here would be positive because X is getting bigger over time. And the velocity here would be negative because X is getting smaller over time.