Transfer of Energy

1. Transfer of Energy Sciences 7e Mme. Goold

2. Kinetic Energy • Kinetic energy is the energy of movement inside an object. • In the case of thermal energy, it’s the energy of the vibration of the particles.

3. Transfer of thermal energy (heat!) • Heat is transfered from a warm substance to a cooler one. • There are three processes • Conduction • Convection • Radiation

4. Conduction • The particles near the source of heat absorb energy and start to move faster. • The particles that move faster start bumping against other particles, increasing their energy and speeding up their movement.

5. Conduction • Particles continue to hit one another and so on and so forth. Thermal energy is transfered across the substance. • Youtube - conduction

6. Conduction

7. Conduction • Demonstration – Nails on a stick

8. Convection • Particles close to the source of heat absorb energy and get warmer. • Particles that are hotter are futher apart (less dense) and therefore they rise.

9. Convection • Cold particles are closer together (more densely packed) and therefore they sink to the bottom and become reheated. • Eureka! Convection • Demonstration – Smoke Stack

10. Radiation • Thermal energy is transfered from the source of heat in the form of a wave. • The wave can pass through matter and even through space.

11. Radiation • Thermal energy is either absorbed or reflected by objects that are in the path of the wave. • This is done WITHOUT particles • Eureka! Radiation • Demonstration (lightbulb)

12. Three methods of energy transfer