Particle theory
Matter is made of tiny particles
Describe movement, distance between particles
Solid - particles touch, fixed, vibrate, don't move
Liquid - close particles, move past each other, random
Gas - More space (avr), Move at hi speeds, any direction
Hotter = more vibration, faster movement, more collision
PSI = gas particles colliding w/ container sides
More freq, energetic = more PSI; more Temp = more PSI