Ex-CIA Spy: China Is Preparing & We're Not Paying Attention! Here's What Happens If They Takeover!

So we have a spring here that has a spring constant of 4 newtons per meter. What we then do is take a 10 gram mass and we put it on top of the spring, and we push down to compress the spring by 10 centimeters. We then let go, and what I’m curious about is…

If I had a time machine, I think I’d go back to when a Mars-sized protoplanet sideswiped Earth in the early solar system, sideswiping our crust, casting billions of tons of rock into orbit around the Earth, which then coalesced to form our Moon. I want, I…

[Music] It’s always fun sitting on sets, watching everybody in costumes. CU of course, it’s the nearest thing to time travel you can kind of get, you know? Everyone disappears if the crews are in a certain way. You just look around, you see these people, …

Hello historians, and welcome to South Central Asia circa 280 BCE. We’re looking at two empires that occupy some of the same area, and we’ve got the Mauryan Empire here. You can see this is the expansion that took place under Ashoka around 250 BCE. So the…

Let’s talk a little bit about DNA cloning, which is all about making identical copies of a piece of DNA. Usually, it’s a piece of DNA that codes for something we care about; it is a gene that will express itself as a protein that we think is useful in som…

Hi everyone, welcome to today’s homeroom. We have a very exciting special conversation with Dr. Fauci coming in a few seconds. But I will make my standard announcement reminding everyone that Khan Academy is a not-for-profit organization. We can only exis…