[Dr. Scott W. Tinker] Earlier we learned that most electricity starts off as heat. Nuclear power is just a sophisticated way to generate that heat. Here we have our solar system models again representing atoms, but this time of uranium. To unleash the energy, we shatter the nucleus. This tiny but very powerful explosion releases neutrons, themselves smaller than atoms, that collide with another nucleus shattering it that releases neutrons, collides with another nucleus and so on. This chain reaction makes the uranium extremely hot which heats the water around it, that heats the water in a different closed-loop, creating steam which turns a turbine and turns the generator. What sets nuclear apart from all other energies is density. There's far more energy per weight in uranium than anything else. Wood powered human civilization for thousands of years. It has an energy density of 16 megajoules per kilogram, but we're going to represent that by a box that's 16 square inches. Sugar, which powers us, is higher at 17, then coal at 25, fat like butter, gasoline, natural gas, and hydrogen at 120. Then, there's uranium. There's not a box around uranium because it wouldn't fit on this board. In fact it won't even fit in this room. It wouldn't fit in this building. In fact, it's larger than our entire lab complex. 46, 55, 120, and 80 million. This phenomenal energy density gives nuclear some remarkable benefits. It means that one nuclear reactor could power an entire city. Except for the biggest dams, they're our most powerful electric plants. They can run at full capacity always on for a year and a half on just one load of fuel, and they can do all this without emitting CO2. Nuclear is the only non-carbon energy that can replace fossil fuels at scale, and easily meet the energy demands of the megacities of the future. But to do so, it would have to overcome some significant challenges, and we'll look at those next.