E(15-1) How is thermal energy transferred? Vocabulary Thermal energy Heat Conduction Convection Radiation Insulation

Thermal Energy The kinetic energy of the moving particles of a substance or object is called thermal energy. The more thermal energy an object or substance has, the warmer it is.

Thermal Energy A thermometer indicates the temperature of the material. Temperature is a measure of the average kinetic energy of the particles in an object or surface. The faster the particles move on average the higher the temperature is.

Thermal Energy In the united states, the weather report usually gives the air temperature in degrees Fahrenheit (F). Water freezes at 32 F and boils at 212 F. Nearly all other countries are using the Celsius (C) scale. water freezes at 0 C and boils at 100 C.

Thermal Energy The amount of thermal energy in an object is related to its mass. If two objects at the same temperature are compared, the one with the greater mass has more thermal energy.

Thermal Energy Transfer Heat is the transfer of thermal energy from warmer objects to cooler ones. Three processes transfer thermal energy Conduction. convection. Radiation.

1. Conduction Conduction is the transfer of thermal energy that results from the collision of particles. Conduction transfers heat only from warmer solid to the cooler solid. Metal is good conductor of thermal energy.

2. Convection Convection is the transfer of thermal energy through a fluid. That fluid may be a liquid or a gas. Convection happens because: Different parts of the fluid have different temperatures. The volume of the warmer part increases, so its density decreases. The warmer fluid moves upward in a current.

3. Radiation Radiation is the transfer of thermal energy as waves. It doesn’t require matter at all. The most familiar source of radiant energy is the sun. Radiation transfers the thermal and light energy to the Earth. Using a microwave to heat a cup of water is transferring energy by radiation.

Insulation Insulation is the substance that conducts thermal energy poorly. Uses of insulation: Quilted or down-filled clothing. Layers of insulation inside the walls and ceilings. ex. Fiberglass.