Particle Theory Part 1 - Heat Definitions and Main Points

Particle Theory of Matter

• Matter is made up of tiny particles that are in constant motion
• Heat is a form of energy that is transferred from one body to another due to a temperature difference

Key Concepts

• A pure substance is a substance that consists of only one type of particle
• The Celsius scale is a temperature scale where 0°C is the freezing point of water and 100°C is the boiling point of water
• The Fahrenheit scale is a temperature scale where 32°F is the freezing point of water and 212°F is the boiling point of water
• The Kelvin scale is an absolute temperature scale where 0 K is the lowest possible temperature

Particle Theory

• The four main points of the Particle Theory of Matter are:
  • Matter is made up of tiny particles that are in constant motion
  • These particles have kinetic energy
  • The particles are in close contact with each other in solids, are farther apart in liquids, and are widely spaced in gases
  • The particles are attracted to each other by intermolecular forces

Scientific Inquiry

• The scientific process involves making observations, asking questions, and testing hypotheses
• A good scientific explanation involves stating a clear question, making observations, and proposing a hypothesis that is supported by evidence

States of Matter

• The three states of matter are solid, liquid, and gas
• Examples of each state include:
  • Solid: ice
  • Liquid: water
  • Gas: steam

Similarities and Differences

• Solids, liquids, and gases have similar properties, such as taking up space and having mass
• They differ in terms of volume, shape, movement of particles, amount of energy, attractive forces, space between particles, and compressibility

Expansion and Contraction

• Gases expand more than liquids or solids when heated because the particles gain kinetic energy and move farther apart
• Solids expand slightly when heated, which is why bridges and railway tracks are built with expansion joints

Temperature and Heat

• Temperature is a measure of the average kinetic energy of particles
• Heat is a form of energy that is transferred from one body to another due to a temperature difference

Thermometers

• There are three main thermometer scales: Celsius, Fahrenheit, and Kelvin
• Each scale is used in different contexts, such as laboratory settings, everyday applications, and high-temperature measurements
• Examples of when to use each scale include:
  • Celsius: measuring temperatures in everyday applications
  • Fahrenheit: measuring temperatures in laboratory settings
  • Kelvin: measuring high temperatures in industrial settings

Kinetic Energy

• Kinetic energy is the energy of motion
• The particles in a substance have kinetic energy due to their motion

Particles and Heat

• When particles are heated, they gain kinetic energy and move faster
• When particles are cooled, they lose kinetic energy and move slower

Bimetallic Strips

• A bimetallic strip is made of two different metals bonded together
• When heated, the strip bends due to the difference in expansion rates between the two metals

Thermographs

• Infrared thermograms are used to measure temperature in various applications, such as medical imaging and building inspections
• Two practical applications of infrared thermograms are:
  • Detecting heat leaks in buildings
  • Monitoring body temperature in medical applications

Changes of State

• Matter can change state from solid to liquid (melting) or from liquid to gas (vaporization)
• Examples of changes of state in everyday life include:
  • Ice melting into water
  • Water evaporating into steam
  • Sweat evaporating from the skin

Heating Curves

• A heating curve is a graph that shows the temperature of a substance versus time
• The melting point and boiling point of a substance can be determined from a heating curve
• The temperature of a substance does not change at certain points on the heating curve, even though the substance is still being heated, due to the energy being used to change the state of the substance.