Searching for the Ultimate Lego Pieces
Most kids like to play and build with Legos. Pieces can be assembled and connected in countless ways to construct vehicles, buildings, working robots, and more. If you’ve ever been to the Mall of America, you know the sky really is the limit.
But what are the equivalent Lego pieces for us? What are we made of? Do human “Legos” differ than those which make up animals or plants? Scientist have been trying to find the answers to these questions.
All living and nonliving things around us, as well as the things very far away from us like stars or clouds, are all made up of stuff called matter. In fact, anything that has mass and takes up space can be considered matter. Finding the fundamental building blocks of matter -- the pieces of matter that make up everything from flowers to the galaxies – is indeed an interesting and meaningful endeavor.
Until the early 1900s, the basic building blocks that make up matter were considered to be atoms. Sometimes two or more atoms bond to form a molecule. For example, a water molecule is made up of two hydrogen atoms and one oxygen atom.
Sometimes, a molecule can be very simply made of two atoms; for instance, a hydrogen molecule is made up of two hydrogen atoms. Others can be very complex, made of many, many atoms. For example, DNA is a linear molecule that is composed of other smaller molecules and it carries the genetic information which is passed from one generation to another.
Beginning in the early 1900s, scientists started to observe that atoms are made from subatomic particles. From various experiments they found that every atom contains a central core called the nucleus, made of particles called protons and neutrons.
The protons are charged particles which carry a positive charge and neutrons are neutral particles. The positively charged nucleus is surrounded by mostly empty space, except for very tiny, negatively charged particles called electrons that orbit the nucleus.
There are 118 types of atoms that have been either discovered or synthesized so far. The simplest atom with only one proton in the nucleus is hydrogen and the atom with 118 protons is known as oganesson (Try pronouncing that right on the first try!) This list can be increased in the near future with the possible synthesis of higher atomic number atoms. More than 90 of these elements exist in nature and some of them are systematized in a laboratory.
Each atom is different with its own physical and chemical property; however, the protons, neutrons and electrons in these atoms are the exact same. So, protons, neutrons and electrons are considered a fundamental Lego piece from which you can make any atom you like.
Recently, scientists have discovered that protons and neutrons themselves are composed of smaller particles known as quarks. Based on the most current scientific understanding, these quarks are truly fundamental particles. “Standard Model” is a theory that explains our current understanding of the nature of matter.
According to this model, there are two types of matter particles called quarks and leptons and the “other particles” are force carrier particles called bosons. There are six quarks and six leptons
The lightest and most stable particles make up the first generation; whereas, the heavier and less-stable particles belong to the second and third generations. The six leptons are similarly arranged in three generations: the “electron” and the “electron neutrino,” the “muon,” and the “muon neutrino,” and the “tau” and the “tau neutrino.”
All stable matter in the universe is made from particles that belong to the first generation; any heavier particles quickly decay to more stable ones.
The only other "family" of particles in the universe is the force carrier particles. Quarks and leptons interact with one another by exchanging force carrier particles.
Today, scientists don't know of anything smaller than quarks and leptons, but they don't know for sure whether these are the simplest building blocks of matter.
Many scientists believe that our current understanding of the fundamental particle is not complete. The search for ultimate Legos that builds everything in the universe continues.
Dr. Yadav Pandit is an experimental nuclear physicist currently working at Allen Community College as a physical science instructor. He writes a column of general interest in science for the Register.