 So this is a really quick video to show the concept of parallax in action. So I have a water bottle and then I've got a nice little border on my wall just as a reference. If I shift the camera position over towards one shoulder or towards the other shoulder, even though the water bottle doesn't move, it appears to move relative to the background. So as I shift compared to the background, there are different things behind. Now this is if the water bottle is up close to me. If I shift the water bottle further away from me and I shift back and forth from one shoulder to the other, it still shifts relative to the background, but it's a much smaller shift. I could do this outside if it wasn't raining and show you that you can see the same sort of effect with a tree or other object that's far away. That depending on how you view it, the objects which are stationary appear to move relative to the background stationary objects simply because you're viewing perspective. Now while this may not be incredibly useful for measuring the distance to a water bottle inside a house, it ends up being very important and very efficient way to measure the distances to stars that are close to us compared to stars that are far away. You'll get the chance to do more parallax experiments in the rest of this lab.