Imagine if you could hold something in your hand that was so small, you couldn’t even see it with your naked eye, yet it held amazing power. This is the case with the nucleus of a uranium atom, specifically Uranium-238, the most common type of uranium found on our planet.
To understand the size of a uranium nucleus, let’s compare it to things we can see and touch. Picture a grain of sand. Now, imagine that grain of sand being 10 million times larger. That’s about the size of a football field! Yet, if that grain of sand was the size of a uranium nucleus, then the whole uranium atom would be the size of that football field. That’s because the nucleus is incredibly tiny compared to the size of the whole atom. In fact, if the nucleus was the size of a marble, the whole atom would be about the size of a football stadium! Isn’t that fascinating?
Even though the uranium nucleus is incredibly tiny, it’s filled with protons and neutrons that carry an enormous amount of energy. When these particles are split apart in a process we call nuclear fission, they release a lot of energy. This is the same kind of energy that powers nuclear reactors and atomic bombs.
Uranium-238 is a very special type of uranium. About 99% of all the uranium found in nature is Uranium-238. What makes it interesting is that it can be changed into another type of element, called plutonium, which can be used to sustain a chain reaction in a nuclear reactor.
Uranium-238 has a very long life. In fact, its half-life, which is the time it takes for half of it to decay into another element, is about 4.5 billion years. That’s almost as old as the Earth itself! Because of its long life and natural abundance, Uranium-238 is responsible for about 40% of the heat produced within the Earth. That’s a lot of heat coming from something so small!