Atoms consist of smaller particles: protons, neutrons, and electrons.
Emphasis on how small atoms really are.
How Small Are Atoms?
A thought experiment: How many atoms (if all were nitrogen) are in a grapefruit?
Imagine each atom as the size of a blueberry.
The grapefruit would need to be the size of Earth to contain all the nitrogen atoms.
Atom Structure and Nucleus
Inside each atom:
Nucleus: Contains protons and neutrons.
Electrons: Located on the outside of the nucleus.
Misleading traditional drawings of atoms; not drawn to scale.
Visualizing the Nucleus
Scaling up the atom to understand nucleus size:
Atom the size of a blueberry: nucleus is invisible.
Atom the size of a house: nucleus barely visible.
Atom the size of a football stadium: nucleus is the size of a marble.
Empty Space in Atoms
Atoms are mostly empty space:
Between the nucleus and the electrons is vast empty space.
Minimal physical matter, mostly empty space with some electromagnetic fields.
Density of the Nucleus
Almost all the mass of an atom is in the nucleus.
Nucleus Density:
Four times 10^17 kilograms per meter cubed, or 2.5 times 10^16 pounds per cubic feet.
Visualizing density:
One-foot box containing nuclei from 6.2 billion (equivalent to world population) cars.
Summary
Atoms are extremely small and mostly empty space.
The nucleus is incredibly tiny but extremely dense.
Comparing atoms in a grapefruit to blueberries in the Earth.
Visualizing the size and density helps understand atomic structure: nucleus as a marble in a football stadium-sized atom and immense density equivalent to fitting all cars in the world into a one-foot cubed box.