Heat Transfer Learning Objectives Use the particle theory

Heat Transfer

Learning Objectives • Use the particle theory to explain heat transfer in terms of conduction, convection and radiation • Recall that heat is transferred from a hot substance to a cooler one

Key Terms • Conduction • Convection • Radiation https: //www. youtube. com/watch? v=C 8 OC 8 q 5 c. X 3 s

What have we learned so far? • Conductors are materials that allow energy to pass through easily • Conductors are usually metals, with the exception of graphite • Insulators are materials that energy does not pass through easily • Common insulators include wood, plastic, fabric and glass

Conduction • When a substance is heated, its particles gain energy and vibrate more vigorously • Vibrating particles hit other particles, causing them to vibrate. • This passes along thermal energy from hot areas to cooler areas https: //content. echalk. co. uk/esa/Science/phys ics/conduction. html

Convection • Occurs in liquids and gases, where particles are able to move more freely • Heated particles (with more energy) take the place of cooler ones. • Thus, heat is transferred from hot areas to cooler areas

Radiation • All substances give off a type of energy called ‘infrared radiation’ • The hotter an object, the more radiation it gives off There are no particles involved in radiation. Therefore heat can travel huge distances without the help of a conductor