How many fundamental particles make all what exists in the universe? In our days electrons, protons and neutrons were considered the fundamental particles making up the atoms. Atoms combined with each other according to some rules to make molecules which are the building blocks of the universe. As the research to probe into the heart of these fundamental particles advanced with the advent of high speed particle colliders, it has been found that itis after all not as simple as it looks. Only electron withstood the test of being the fundamental particle. It was shown that neutrons and protons are formed from other particles which have been observed in these particle smashers. We now know that protons and neutrons can be formed from two fundamental particles called up and down quarks. So along with electrons, all that is present can be made from up and down quarks.
But till date 12 fundamental particles have been discovered. So what are these needed for. Whether it is finally 12 or any number is also a guess because theories can get shattered by the availability of more powerful smashers.
It is known that energy and mass are the two sides of the same coin. From the mass we can create energy and vice versa. How particles get different masses?
It was proposed that space is filled with a energy field called Higgs field. If we consider it was water in a container for analogy then it is continuous with break. Water is made of molecules of water which is H2O. These molecules fill all the space occupied by water. It means water molecule is smallest unit . By analogy smallest unit of energy or the particles which make the Higgs field are called Higgs Boson. It is this field which gives the particles their different masses which represent the extent of its interaction with the field.
In the particle accelerators, atoms moving almost at 99% or more the speed of light are collided with each other. They get converted into energy field. This energy field then gets converted into numerous sub atomic particles which are recorded. It is hoped that out of these particles, the Higgs Boson will show up. At least CERN which is doing the research with giant colliders having perimeters of almost 22 kilometers announced that they have observed a particle which is most like the Higgs Boson.
Efforts will continue. Since this particle which stands as the central entity in the Standard Model which is currently the most successful system to explain the existence of the sub atomic particles, will be successfully discovered. Since it is so elusive , it has been nicknamed the “God Particle”
There are atoms which have same chemical properties but different atomic weights. They have same atomic mass because number of protons are identical but additional neutrons make then different in weight. Such atoms are called isotopes.
For example carbon which has 6 protons and 6 neutrons have an isotope which have 6 protons but 8 neutrons. They are presented as C14 and C12. Addition of protons make them less stable and many of them are radioactive. The rate at which a particular atom decays is independent of temperature, light or darkness. During decay the atom is trying to achieve state of minimum energy and produces atoms with lower atomic numbers and energy.
The rate of decay is expressed in terms of half life. For example a given weight of C14 atoms will become half in weight in 5600 years. precisely. Then the remaining mass will again take 5600 years to become 1/4 th and so on. This property has many uses and one of the most popular one is carbon dating to determine the age of wood.
Vegetation absorbs CO2 and the same C14/C12 proportion is found in wood as in the atmosphere as long as the tree is alive.But, after a tree is felled it no longer absorbs CO2 from the atmosphere. Inside the dead wood, the C14 brothers slowly disappear, and are not replaced. So, a piece of wood from a Pharaoh’s tomb contains a far lower C14/C12 proportion than a tree that has recently been felled. This type of clock is particularly useful to archaeologists, and allows them to date wood between 200 and 20,000 years old. The ratio of C14/C12 is measured using a ratio recording mass spectrometer.
Atoms are thought to be the smallest entities which take part in the chemical reactions. They join with each other in different ratios to form the molecules which then combine to form macro-molecules. The molecules can exchange atoms with other atoms or molecules to give rise to different molecules.
Atoms are not the fundamental particles of the matter. Even an atom contains protons and neutrons confined in a very small space called nucleus in the core of the atom and electrons occupy rest of the space. Electrons are negatively charged particles and counter balance the positive charges on the protons in the nucleus. Since their charges are equal and opposite, their number are identical. There are neutrons also which are similar to protons in the weight but have no charge.
Now come the puzzling bits. how do the electrons orient themselves inside a atom. If they are really the particles as we think then they must be having a definite volume. Since we say that the space occupied by the electrons is many times bigger than nucleus and size of electrons is very small, then there must be some empty spaces inside the space outside nucleus. The question is if this is so then what is there which occupies that space. Is it a vacuum?
All these observations force us to conclude that reality is much more complicated than we think. It is usual in the science to construct the simplified models which are capable of explaining a certain set of data. That is why the concept of matter and wave duality was propounded. According to this principle, entities behave both as particle and wave simultaneously. This has been proved in famous experiments in which electrons behave as waves. The famous equation governing this wave nature is Schrodinger’s equations.
Similarly, it is fundamental truth that particles with similar charges repel each other. Then how come are many positively charged protons are crammed into such a small volume. Why do not they fly apart? Why is the arrangement quite stable with nucleus remaining unchanged for years. Again the things are not what they are thought to be. It has now been proved that even protons and neutrons are not the fundamental particles but are made of strange type of particles called Quarks. It has been found that mass of the nucleus is not equal to aggregate mass of protons and neutrons it contains. It is lesser than that. Where is the mass that is lost. It is present in the form of energy and amount of energy is according to Einstein’s equation E=mass multiplied by speed of light squared.
That is why we are making atom smashers where we break apart the atoms by bombarding them with particles approaching speeds of light and analyze the particles which are formed during collision.