 # Thermal energy and Heat. Thermal energy Thermal energy is the total kinetic energy of all particles in a substance Measured in joules (J) This is not.

## Presentation on theme: "Thermal energy and Heat. Thermal energy Thermal energy is the total kinetic energy of all particles in a substance Measured in joules (J) This is not."— Presentation transcript:

Thermal energy and Heat

Thermal energy Thermal energy is the total kinetic energy of all particles in a substance Measured in joules (J) This is not temperature, the amount of particles matter for thermal energy

Heat Heat is the energy transferred from an object at a higher temperature to an object at a lower temperature Heat energy always flows from hot to cold Heat is measured by calories (cal) or joules (J) A calorie is the amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius. 1 cal = 4.18 J

calorie and Calorie The Calorie is commonly used to measure heat in terms of food A Calorie is actually a kilocalorie To measure how many Calories are in food we burn the food inside a calorimeter and record the temperature change.

Heat and Thermal Energy Thermal energy is a physical property, heat is the energy involved when this property changes Adding or subtracting heat energy can change the state of a substance

Conduction Conduction is the transfer of energy as heat through direct contact Conduction can happen in a single object. Energy transferred from the warmer part of the object to the cooler part. A conductor is a material that transfers heat very well. An insulator is a material that is a poor conductor of heat.

Convection Convection is the transfer of energy as heat by the movement of a liquid or gas. Convection occurs when a cooler, denser mass of gas or liquid replaces a warmer, less dense mass of a gas or liquid A circular motion of particles is formed called a convection current.

Radiation Radiation is the transfer of energy by electromagnetic waves. Examples: visible light, microwaves, infrared light When radiation is emitted from one object and absorbed by another the result is often a transfer in heat. Transfer from hot to cold Can travel through space!

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