Subtitles section Play video Print subtitles So I'm down in West Vancouver, British Columbia, which is where I grew up. And at the local beach there is this 2.5 ton granite sphere that was made to have a tolerance of to hundreds of a millimetre. This is amazing granite sphere, and it's floated on a thin layer of water, and it just presents an amazing opportunity to study inertia. And that's why I'm down here to have a chat with the with some of the people going by about why the globe spins and in fact, why the Earth spins. Why does the Earth's spin? Why does it turn like that? I think the gravity for keep us down on the ground, right? Gravitational pull. How does that cause the earth to spin again? My basic science fails. It's gravity and he guesses, looking gravity. Well, yeah, way you you. It's not stopping. Would you agree with me that? So why is that some sort of force that's you think there's a force down there pushing it? Yeah, I'm gonna go because the up thrust from the water is probably angled in such a way that it's because it's a spherical shape. It's probably pushing on it at an angle. So it spins constantly. Yes. What is a centrifugal force that keeps it? Keeps it going. What is that force? Where does that force come from? Isn't Air Force that keeps going in their force? Working around within, within, within the S cores. They're not something that drives and dictates, said centrifugal force. It's the law of inertia in it. What's the law of inertia? Every action equal and opposite reaction force in inertia maintains this. But inertia, which is great idea is not a force. How would you define? It's just the tendency of all objects with mass to maintain their state emotion. Okay, so if they're stationary, they want to stay stationary. If we anthropomorphize. Yes. Moving said under your authorized objects wanted, want to keep you basically whatever motion they have, they like to continue in that state. Yes, the Earth does that without any forces. This does that without any force.