HEAT & TEMPERATURE

Nota:

• It is the average kinetic energy of a very large group of atoms or molecules. The kinetic theory of gases describes a gas as a large number of small particles (atoms or molecules), all of which are in constant, random motion. The rapidly moving particles constantly collide with each other and with the walls of the container. Kinetic theory explains macroscopic  properties of gases, such as pressure, temperature, viscosity, thermal conductivity, and volume, by considering their molecular composition and  motion.

Nota:

• It is measure of the average kinetic energy of the particles in a sample of matter, expressed in terms of units or degrees designated on a standard scale.

1. Thermal Expansion

   Nota:

   • It is occurs when bodies increase their temperature.
2. Measurement
   1. Scales
      1. Celsius
      2. Fahrenheit
      3. Kelvin
   2. Thermometers

      Nota:

      • Mercury Alcohol Digital Air

1. HEAT

   Nota:

   • Heat is the transfer of energy from one system or body with a higher temperature to one with a lower temperature
   1. Units

      Nota:

      • Joules Calories 1 calorie = 4.18 joules 1 joule = 0.24 calories
   2. How is Transferred?
      1. Conduction

         Nota:

         • - It is the process by which heat is transmitted from one point to another in a solid. - Thermal energy is transmitted but not matter.
         1. Thermal conductivity

            Nota:

            • - Thermal conductors: they transmit energy quickly from one point to another. - Thermal insulators: they transmit thermal energy slowly from one point to another.
      2. Convection

         Nota:

         • It is the process by which thermal energy is transferred from one point to another in a fluid (liquid or gas) because the fluid is moving due to the changes in their density. In this process, thermal energy is transmitted through the transport of matter
      3. Radiation

         Nota:

         • Radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium
2. THERMAL EQUILIBRIUM

   Nota:

   • When two systems or bodies that are in a state of thermal disequilibrium com into contact, the one with the higher temperature transfers thermal energy to the one with the lower temperature until they are in a state of themal equilibrium