 and we're going to do a little science today. You've probably seen this particular demonstration before, but you may not have realized what it really means and the real science underlying it. So the demonstration is very simple. I've got a balloon with air in it and a source of flame. Now, when I lower the balloon down to the source of flame, guess what? Boom, the balloon pops. Now, I've got the same kind of balloon here, but this one has water in it. Just half an inch, well, a couple inches of water. Same thing, lower it on here. And notice the real difference here. This balloon is not popping. Indeed, I can stand here and hold this flame on the balloon for quite a while and it won't pop. So why is this? What's going on? Why doesn't the balloon pop? What does this tell us about water? And what does it tell us about science in general? The reason the balloon pops in air is because the flame melts the balloon. The air inside the balloon is under pressure. The skin melts and pop. The balloon's gone. When we do it with water in it, however, the water removes the heat from the skin of the balloon faster than the skin can heat up. The skin never reaches a critical temperature and never melts. The water just gets very slightly warmer and the balloon stays intact. And what this tells us is that water has tremendous heat capacity. It can pick up heat from the atmosphere. It can pick up heat from a flame and it holds it and moves it around. The real implication of this is when you think about this on a global scale, think of the flame as the sun, the water balloon here as the ocean. In the tropics right there where the flame is hitting, the water is heating up and moving around the skin of the earth. It's transferring heat all over the surface of the earth and that's why the earth is actually as habitable and temperate as it is. If it weren't for this amazing property of water, the tropics would be very, very hot and the poles would be incredibly cold. The earth would not have very much space for life, only a narrow band between a very hot and a very, very cold region. But as it is because of the heat capacity of water, the earth is habitable virtually around its whole surface. That's it. Real simple. Thank you.