Science Unit 4 Notes 3

Introduction to Matter and Kinetic Theory

• All matter is made of tiny particles in constant motion

• Particles behave in different states

• Understand states of matter and particle behavior

Kinetic Theory Basics

• Particles are always moving, even when we can’t see them

• Temperature measures the average kinetic energy of particles

• As particles move faster, they spread out

• Example: Bridges have expansion joints to allow for thermal expansion

Four States of Matter

• Solids: Tightly packed particles with fixed shape and volume

• Liquids: Particles flow and take container’s shape

• Gases: Particles spread out with no fixed shape or volume

• Plasma: High-energy state where electrons separate from atoms

Phase Changes

• Melting Point: Energy needed to change from solid to liquid

• Boiling Point: Energy required to transform liquid to gas

• Sublimation: Direct change from a solid to gas

Exploring Fluid Properties:

• Buoyancy: Upward force fluids exert on objects

• Archimedes’ Principle: Buoyant force equals weight of displaced fluid

Fluid Pressure and Flow

• Pascal’s Principle: Pressure spreads equally through a fluid

  • Used in hydraulic car lifts and machinery

• Bernoulli’s Principle: Fluid velocity affects pressure

• Viscosity: A fluid’s resistance to flow

Understanding Gas Behavior

• Gases have large spaces between particles

• Boyle’s Law: P1V1=P2V2

• Measured in Pascals (Pa)

• Gases can be compressed easily

Gas Laws: Boyle and Charles

• Boyle’s Law: Pressure and volume have an inverse relationship

  • When volume decreases, pressure increases (vice versa)

• Charles’ Law: Temperature and volume are directly related

  • Warm air expands and rises

Water

• Water behaves differently from most other liquids

• Expands when it freezes, unlike most liquids

• Ice is less dense than liquid water, which is why it floats

• Allows aquatic life to survive in cold climates

• When water freezes, molecules spread out in a crystal-like structure