Changes of state Van der Waals forces Making things happen Commentary

Johannes Diederik van der Waals chemistry

Changes of state

• Atoms in a gas are not infinitely small
• or unaffected by one another.
• They are not merely kinetic Newtonian objects
• with probable velocities
• moving at random far apart in space.
• If they were, the pressure of a gas
• would vary smoothly with its temperature.
• Johannes Diederik van der Waals
• modified the kinetic theory of gases
• developed by Maxwell and Boltzmann
• to account for a molecule’s size
• and its affects on its neighbors.
• His equation let him predict
• the phase transitions between stable states
• where a gas becomes a liquid
• or a liquid becomes a gas.

Van der Waals forces

• Tiny hairs on the toes of a gecko
• stick to leaves, ceilings, even plate glass
• because they get extremely close
• where small temporary
• or permanent polarizations
• cause molecules to act like magnets.

Making things happen

• Science cannot predict when a look
• becomes a laugh.
• Two magnets may repel or attract.
• Although a state of mind may be valuable,
• it would be more profitable
• if it were more predictable.