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