H   H
The Mighty Atom
            So most atoms are ancient. They have existed through imponderable ages, recycling through the universe in innumerable forms, both nonliving and living. In this sense, you don't "own" the atoms that make up your body--you are simply their present caretaker. There will be many caretakers to follow. Hewitt                       Hewtitt_343      
          Atoms are Ancient
and Empty
"We are literally breathing one another."
The Evolution of the Atom in our Minds I, II
        Proton                             Neutron      
          The most fundamental unit of Matter,
or are they?
It's not the nucleus that counts. . .
it's the last few electrons that make all the difference.
Chemistry is often described as a central science because it touches all the other sciences.
It springs from physics principles and it serves as the foundation of the most complex science of all---biology.
      Since protons have a positive charge and like charges repel.
Why do they want to group together inside a tight nucleus?
      Since the atoms in my hand are mostly 'space'.
Why can't I put my hand through a wall that is also mostly 'space'?
Force and Particles
All the Ingredients
Gravity may be the weakest of all forces
           . . . but certainly the most persistent!
Although Newton, discovered the Law of Universal Gravitation. It was Cavendish that measured the constant G which made it possible for scientists to use Newtons law.

By measuring G, Cavendish was able the find the mass of the Earth as well as it's density! Later Kepler, used G, to find the mass of the sun.
The Force of Gravity
is reduced
by 1/4 if the distance
from the earth
is doubled.

The Force of Gravity
is increased
by 9 times if the distance
is cut to a third.
The Electric Force - like charges repel, opposite charges attract
The Electric Force is quite different from the Gravitational Force.

It is trillions and trillions of times stronger!

The Electric Force is attractive as well as repulsive.

The Electric Force takes place between charged objects.

Like protons and electrons
And, the door and your hand.
like poles repel, opposite poles attract -The Magnetic Force