Transcript: The only way in which humans have so far harnessed fusion is in a hydrogen bomb, the most violent product of human creation. We’re obviously interested in fusion as a power source for a simple reason. What goes in in fusion is light elements like hydrogen, and what comes out is deuterium or helium or tritium. Other light elements, if they are radioactive they have very short half-lives and decay quickly. Fusion compared to fission is therefore a very clean energy source and...

Transcript: The decay of a massive atomic nucleus with the release of particles or energy or the splitting of a massive nucleus into two or more pieces is called fission. In fission the sum of the fragments is less than the mass of the original nucleus. The excess is released as energy according to E = mc2. Fission is a highly efficient energy source. When a single atom of uranium 235 decays it releases three times ten to the minus eleven Joules of energy. Not much for a single atom, but...

Transcript: The mass of any atomic nucleus is less than the separate masses of its protons and neutrons. The difference is the binding energy. In other words sticking protons and neutrons together somehow causes some of their mass to vanish. The answer is connected with Einstein’s equation E = mc2. Mass and energy are really two different forms of the same thing so the vanishing mass of the protons and neutrons is simply converted into energy, and that’s the idea behind fusion. The...

Transcript: The universe is full of things that are held together by forces: atoms, molecules, solar systems, stars, and galaxies. The binding energy of a system is the energy required to take it apart. For example, a speed of eleven kilometers per second corresponds to the kinetic energy needed to liberate anything from the gravitational binding energy of the Earth, or consider an atom. The binding energy of a hydrogen atom is a tiny quantity, 2.2 x 10-16 Joules. This means that any...

Transcript: The equivalence between mass and energy denoted by the equation E = mc2 has profound consequences for the way we look at the physical world. We know that energy comes in many forms, and mass is just one of these. In a sense mass is potential energy since normally it is frozen in the form of stable particles. In the equation E = mc2 the arrows go both ways. Just as mass is a form of energy, so energy is a form of mass. A rapidly moving car has slightly more mass than a...

Transcript: The nucleus of the atom contains a prodigious potential energy source. Mass and energy are related by Einstein’s famous equation E = mc2. Since c is a very large number, three hundred thousand kilometers per second, c2 is an even larger number. So a tiny amount of mass is equivalent to a huge amount of energy. When you plug the numbers in you can see how dramatic this is. The mass-energy equivalent to the tip of a pencil lead is sufficient to run a family home for a day. The...

Transcript: Working early in the twentieth century physicist Marie Curie was able to show that radioactive processes released millions of times more energy per atom than any chemical process known. Marie Curie was a pioneer. With her husband she was the first to isolate a radioactive element. She was the first female professor in the six hundred year history of the Sorbonne. She was the first person ever to win two Nobel Prizes; however Marie and many others who worked on radioactivity...

Transcript: The three basic types of radioactive decay are called alpha, beta, and gamma decay. In the alpha process an atom spontaneously emits a helium nucleus. Helium nucleus contains two protons and two neutrons so alpha decay reduces the atomic number by two. In beta decay a neutron decays into a proton, an electron, and a neutrino. A neutron is only stable when bound in an atomic nucleus. Free neutrons will decay radioactively. The final type of emission is called gamma radiation....

Transcript: Radioactive decay is a phenomenon of the atomic nucleus. In these processes an element changes its chemical properties, that is its atomic number, by the emission of particles and or radiation. Radioactivity is a random process. It’s impossible to predict exactly when a particular radioactive decay will occur. However, in a collection of atoms there is a well defined half-life or time that it takes one starting point, that is the parent isotope, to turn into the decayed...