What are elementary particles made of?

Atoms, nuclei, particles: smaller, smaller and smaller

Are atoms elementary particles?

No. Atoms consist of a nucleus surrounded by a shell of electrons. The core, in turn, is made up of two building blocks: the protons (positively charged particles) and the neutrons (neutral).

Atoms are already tiny, the atomic nucleus is ten thousand times smaller and protons and neutrons are one step smaller. Nevertheless, they also consist of other particles, namely of those whose size cannot be stated at all: the quarks. There are six different types of them, and two of them, the "up quark" (u) and the "down quark" (d), form the proton (uud) and the neutron (udd) in different combinations. What is special about quarks: They do not exist as free particles, but only as "trapped" ones. They are strange in general, because the electric charge of a quark is not whole but "broken": It is always either exactly 1/3 or exactly 2/3 of the elementary charge (the charge of the electron).

The quarks form one group of the "actual" elementary particles (one also speaks of fundamental particles). The electron is the most important representative of a second group of elementary particles, the leptons.

Is there a "cement of matter"?

Yes, these are the electrons, because they almost alone produce all manifestations of the matter known to us. They keep the atoms of a body at a distance, neutralize the positive charge of the atomic nuclei, so that atoms can even come together to form solids, and they determine the different properties of the chemical elements as well as the nature and strength of the bonds that the elements form with one another. The electrons are so tiny that not even their diameter is known.

Can fusion reactors meet our energy needs?

Yes, but not in the immediate future. It is true that we can easily generate energy through the fusion of atomic nuclei - just like the sun, which shows us this day after day: It releases unimaginable amounts of energy through the fusion of hydrogen nuclei. The tiny fraction that it radiates on earth every year is 7,000 times greater than the annual energy consumption of the world's population!

Unfortunately, even after 50 years of fusion research, there are still many unsolved technical problems. The fusion fuel has to be heated to over ten million degrees, because only then are nuclear fusions possible. He must not touch the walls of the combustion chamber. This extreme state of matter, known as plasma, could be achieved in test reactors such as the “Joint European Torus” (JET, Culham), but only for a short time. The question of possible radioactive pollution of the environment also arises with fusion reactors, but because of the short half-lives of the radioactive materials (e.g. 2.73 years for iron-55) it is not as explosive as with nuclear power plants. Become radioactive v. a. the metal walls.

What is nuclear fission?

If an atomic nucleus contains too many protons, it is unstable because of their mutual electrical repulsion. Such nuclei are transformed into stable ones by emitting small particles (“♋-” or “♌-particles”) and high-energy radiation (“♑-quanta”).

Some heavy nuclei, such as uranium-235 or plutonium-239, split into two medium-sized nuclei. To do this, they first have to "capture" a free neutron, but this so-called nuclear fission also releases large amounts of energy and neutrons - so that in principle a single neutron is sufficient to split large amounts of uranium in an uncontrolled chain reaction. That case would be an atomic bomb. In a nuclear power plant, neutron-absorbing control rods prevent more than one neutron per fission from triggering a new reaction.

Did you know that …

the atomic diameter is only one hundred thousandth of a biological cell?

do you give the mass of elementary particles using a unit of energy? This is possible because of the Einstein relationship E. = mc² the mass m and the energy E. are equivalent.

the structure of the electron shell of an atom is very complicated? Similar to an onion, it consists of several superimposed shells, each of which has complicated shapes ("orbitals").

the physicists detected dozens of "elementary particles" in the 1960s? It was only the American Murray Gell-Mann who succeeded in bringing order to this "particle zoo" with his theory of quarks. For this he received the Nobel Prize in 1969.

the largest particle accelerator LHC will be installed in a ring tunnel with a circumference of 27 km? The accelerator at the European nuclear research center CERN near Geneva, which was completed in 2007, consumes energy like a small town.

Accelerator experiments generate such unimaginable amounts of data that the fastest computers in the world are used there?