There are more atoms in a grain of sand than there are grains of sand on earth.
Each time we inhale, we are using atoms that were once a part of everyone who ever lived (before 7 years ago).
Nearly all the mass of an atom is concentrated in the atomic nucleus, which occupies only a few quadrillionths of the atom's volume. These are so dense that if bare atomic nuclei could be packed against each other into a lump 1 centimeter in diameter (about the size of a large pea), the lump would weigh 133,000,000 tons.
- Conceptual Physics by Paul Hewitt
