### force | attraction | bond:

Strong bond
* Most strong bonds have energy
  - high energy
  - low energy
* Some strong bonds produce crystal.
* are difficult to break
  - relatively inflexible, so weak bonds, such as hydrogen bonds
* exist between females and their calves.
* have low chemical energy and weak bonds have high chemical energy

Weak bond
* Some weak bonds make minerals.
* make for fragmentation.
* result of too much clamp pressure.

### force | attraction:

Chemical bond
* All chemical bonds form because electrons are placed simultaneously near two positive nuclei.
* Most chemical bonds are created by atoms
  - electron atoms
  - hold atoms
  - produce energy
* Most chemical bonds release chemical energy
* Some chemical bonds enhance stability
  - hold materials
* allow charged elements, ions, to combine and form compounds.
* are attachment
  - electrical in nature
  - electromagnetic in origin, but can be modeled well by tiny springs
  - much like springs
* determine how much and how quickly arsenic moves.
* involve the sharing of electrons between two atoms.
* is attraction
* link atoms to form molecules.
* make molecules behave differently from the network of individual atoms they contain.
* represent another form of potential thermal energy.
* result from the sharing of electrons between atoms.
+ Quantum mechanics, Uses of QM: Basic physics ideas :: Mechanics :: Mathematics :: Nuclear physics :: Quantum mechanics
  * Electrons surround every atom's nucleus. Chemical bonds link atoms to form molecules. A chemical bond links two atoms when electrons are shared between those atoms. Thus QM is the physics of the chemical bond and of chemistry. QM helps us understand how molecules are made, and what their properties are. For a good foundation see 'The Nature of the Chemical Bond,' by Linus Pauling.

### force | attraction:

Gravitation
* Most gravitation involves interaction.
* Some gravitation has magnitudes.
* acts as the driving force via the density difference of particles and fluid.
* constant impelling force.
* crushes protons and electrons together despite their electrostatic repulsion.
* defines our everyday life and the structure of the universe.
* holds the universe together
  - together the hot gases in the sun
* is drifts
  - freedom
  - one of the most studied phenomena in physics
  - the attraction of two objects with mass
* is the force that acts between masses
  - which creates matter's time dimension by consuming space
  - only force which continuously tends to pro- duce isostatic readjustment
  - universal force of attraction between all matter
* universal force of attraction acting between all matter
  - that each mass exerts on any other mass

Gravitational attraction
* Some gravitational attraction causes gases.
* acts to accelerate two objects with mass towards each other.
* causes galaxies to cluster.
* holds the planets in their elliptical orbits around the Sun.
* is additives
  - based on distance and is stronger when the bodies are closer
* main cause of perturbations.
* moves huge clusters of galaxies around in ways that can be measured.

### force | attraction:

Gravitational force
* Most gravitational forces act on layers
  - pull particles
* Some gravitational forces depend on locations.
* acting on every particle by every other particle causes the cloud to condense.
* acts on all bodies in proportion to their masses.
* add together.
* are only recognizable as the masses of objects become large.
* causes every object to attract every other object.
* create tremendous pressure and temperatures in the core
  - warps in space-time
* determine the movements of the stars within a galaxy.
* hold astronomical bodies together and in orbit about one another.
* is an attraction between masses
  - inversely proportional to the distance between two objects squared
  - much weaker than repulsive electric force
* keep Europa's interior warm.
* vary inversely with distance.