Jose Ruiz Ana Reyes

What’s life without atoms? Everyday, you either hold, breathe or eat atoms. Your whole life is based on atoms. The whole world is made up of atoms! When you take a simple breath, you inhale millions of nitrogen and hydrogen atoms! Even when you eat you, your body ingests carbon, nitrogen and carbon atoms! Go ahead, pick up a book, a pencil or a pen, now you’ll be holding an object that is made up of atoms! Now lets discover how it all began …

Atomism: Wind, Earth, Fire, Water Model  Atomism was developed by Leucippus and Democritus.  Atoms are undividable; there is no difference between an atom’s parts.  Atoms have size, shape and weight.  Atoms move in empty space

Wind, Earth, Fire and Water Model  To Aristotle, there were only four different types of atoms. These atoms came to be wind, earth, fire and water.  It was believed that everything on earth was made up of ONLY these four elements.  This theory was suggested around 450 BC  The idea that these elements were all made up of matter became the foundation of medicine and philosophy for two hundred years.  Everything was made up of a mixture of these four elements!

The Solid Sphere Model John Dalton presented his atomic theory in  1. Matter is made up of atoms that are indivisible and indestructible.  2. All atoms of an element are identical.  3. Atoms of different elements have different weights and different chemical properties.  4. Atoms of different elements combine in simple whole numbers to form compounds.  5. Atoms cannot be created or destroyed. When a compound decomposes, the atoms are recovered unchanged. Dalton viewed the atom as a solid sphere

The Plum Pudding Model  Joseph John Thompson introduced the idea of the plum pudding model in  The idea of the plum pudding model is that every atom is positively charged with something inside of it called the “pudding” or electrons.  This idea was proposed based on the cathode ray experiment.

What was the cathode ray experiment?  A cathode is a negatively charged terminal.  In a cathode ray tube, this terminal is a heated filament, much like the filament seen in a light bulb.  The filament is contained inside a vacuum within a glass tube. Inside the tube, a beam of electrons is allowed to flow from the filament into the vacuum.  The electron’s flow comes naturally.

The Nuclear Model  Ernest Rutherford developed the nuclear model.  He tried explaining the alpha particle scattering by using the gold foil experiment.  Alpha particles are heavy particles with twice the positive charge of a proton.

What was the gold foil experiment?  The purpose of the Gold Foil method was to illustrate Rutherford’s idea of alpha particles.  The way this worked was by using a thin gold sheet placed in the center. He tried to shoot alpha particles through the gold sheet in order to prove his idea.  The results were not what he expected. Most particles went straight through, but some of the alpha particles reflected back in different angles.

The Planetary model  Ernest Rutherford discovered that the atom is basically, empty space. - Protons and neutrons occupy a region called the nucleus.  Electrons orbit the nucleus.  It is known as a planetary model because the gravitational force in a solar system and the electrical force are similar.  The positively charged nucleus and the negatively charged electrons in an atom are the same form.  It helped the spectrum of the hydrogen atom!

The Electron Cloud Model  In the Erwin Schrodinger and Werner Heisenburg developed functions the clouds in which electrons would be found.  In the Electron Cloud model, an atom consists of a dense nucleus composed of protons and neutrons surrounded by electrons that exist in different clouds at different energy levels.  This model shows that electrons are no longer showed as particles moving in an orbit.  Meaning that we should not be able to see the particles ; they will just be seen as clouds around the nucleus.

In the end …  We really enjoyed working on this project because we learned many different things about atoms, electrons, alpha particles and how they work.  We found out who created the solid sphere model, who came up with Atomism as well as who came up with the idea of the plum pudding model, the planetary model, and the electron cloud.  Over all this project was fun to work on, it was very interesting and it was a way to learn more about the things scientists like; John Dalton, Ernest Rutherford and J.J. Thomson invented and how they created experiments to support their thinking.

Which is which?!