Top Highlights

• all things are made of atoms—little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another
• 10−8 cm is called an angstrom
• the pressure times the area is the force).
• the pressure is proportional to the density.
• in a solid the atoms are arranged in some kind of an array, called a crystalline array,