States of Matter: Solids
Physical ScienceChapter 5.2
Solids Thermal energy cannot overcome
intermolecular forces of attraction Physical properties of solids:
Density Strength - maintain shape under force
(Brittleness) Elasticity - stretch and return to same shape Ductility - bend without breaking (form wire) Thermal conductivity - transmit heat energy Electrical conductivity - allow electricity to flow
Crystalline Solids Crystalline solids
have molecules arranged in orderly, repeating patterns
Amorphous solids have molecules arranged any which way
Salt, water, metals, most naturally occurring solids
Polymers Polymers are made of
long chains of repeating molecules
Plastics are amorphous solid polymers
Melting point above room temp, but less than metals
Good strength and elasticity
Heat Conduction and Solids Heat conduction is
the transfer of heat by direct contact.
Hand, spoon, cocoa Transfer of energy Thermal equilibrium
occurs when two bodies have the same temperature.
Thermal Conductors and Insulators
Solids conduct heat best because molecules are close together
Good electrical conductors are usually good thermal conductors
Insulators are poor conductors of heat
Heat does not travel through a vacuum