If I want to know exactly how a motor works, I have understand how each part works and how it contributes to the motor's ability to make a car go forward. For instance, I have to understand radiator and what it does. The radiator helps to keep the engine cool so that the motor does not get to hot and shut down. I have to understand what the carburetor does, how the battery is important, etc. to really be able to describe why a motor makes a car go forward. To say that it just turns the wheels is not a complete understanding of the motor. To completely understand matter, its properties, and it characteristics, we must understand all of its parts as well. The smallest part of matter, is an atom. So to understand matter, we must understand the atom, its properties, and its characteristics.
The Atom
Atoms make up
all matter but they are extremely tiny. One atom is more than a million
times smaller than the thickness of a human hair. Through many experiments,
scientist have discovered that an atom are made up of 3 even smaller particles.
These particles are called protons, neutrons,
and electrons and are also referred to
as subatomic particles. Each atom has a definite number of each of these
particles which define what type of atom it is. Protons and neutrons
are held in the atoms center which is called the nucleus.
The nucleus contains most of the mass of the atom because protons and neutrons
are much more massive than electrons. One proton or neutron weighs
around 1,836 times more than an electron. Protons have a positive
electric charge while electrons have a negative charge/ Neutrons have no
charge.
Over the years, many different models for the atom have been developed. These models have changed and evolved as more information about atoms has been discovered. The models describe what the atom looks like at a sub particle level, i.e. where the particles are located, how the move, and the forces that hold the atom together. The first model of the atom was J.J. Thomas's Plum Pudding model, which described the atom as protons and electrons mixed all round, like chocolate chip cookie dough. Another early but important model of the atom was Bohr's Atomic Model. Bohr's model is shown in the picture above. He described the atom as a nucleus with electrons orbiting around it just like the planets orbit the sun. Bohr's model has now been replaced with the most recent model of the atom, the quantum mechanical model. Quantum Mechanics is the study of the motions of subatomic particles and the forces inside an atom. This model does not have the electrons orbiting the nucleus in a path but rather their motion is more random motion. Quantum Mechanics has used complicated mathematical equations to come up with this new model of the atom and its motion. This area of study continues to examine atoms and the phenomena surrounding them in order to develop a better understanding of the atom. There is still a lot we have to learn about the atom but we use the models we have now to understand the atom to the best of our abilities now.
For many students atoms are a term they have already heard, so we must clarify and adjust the ideas and definition of atoms which students already have from their previous experience. Learning more about the atom and excepting what has been stated here, requires you to mold the information into those preconceived ideas. To learn more about the ideas which students have learned about atoms, please click here.