3 Types of Heat Transfer

1. 3 Types of Heat Transfer

2. Heat Transfer • The word “transfer” means to carry across. • When heat transfer occurs, the energy is carried through or across from one solid, liquid, or gas to another • 3 types of heat transfer • Conduction • Convection • Radiation

3. When the energy of the sun hits an object, some of the sun’s energy is transferred to the object’s molecules, heating them. When heat is transferred by invisible waves is this is called radiation. When a person touches that warmed object then some of the energy in the object’s molecules is transferred to the molecules in the person’s skin. This transfer of heat is called conduction. If the heated molecules move to another location, this is called convection.

4. Transfer of Heat Energy Activity • Students pretend to be the molecules in an object • Stand in a circle and hold hands • Student will be touched to indicate that the sun is warming this molecule. • That person clenches his right hand around the left hand of the person whose hand (s)he’s holding. • That triggers this individual to then squeeze his/her right hand, pressing on the left hand of the person whose hand (s)he’s holding.

5. Conduction • Transfer of heat through a solid or between a solid and another solid, a liquid or a gasthat is in contact with it. • Occurs in only one direction (from warmer to cooler)

7. Convection • Transfer of thermal energy by moving particles in fluids-liquids and gases • Circular pattern of moving particles (convection current) • Heat transfers from hotter region to cooler region

9. Radiation • Does not involve the movement of particles • Transfer of energy by invisible waves given off by the energy source • Heat transferred by invisible waves is called infrared waves • All hot solids, liquids, and gases radiate invisible heat waves • When invisible waves of radiant energy come into contact with a solid, the particles in the solid vibrate faster • Coloured solids absorb and reradiate infrared waves, but transparent solids, liquids, and gases allow waves to pass easily through them

11. Heat Transfer Song • http://www.educationalrap.com/song/radiation-conduction-convection.html

12. Heat Transfer Summary