Radiation Conduction Convection Which would you rather be??? (C) Copyright all rights reserved

Conduction: The transfer of energy from one object to another object through direct contact (touching). Example: A hamburger touching the grill; the burger has a small amount of energy, and the hot grill has greater energy. Energy is transferred to the burger from the hot grill. (C) Copyright all rights reserved

(C) Copyright all rights reserved Burger anyone ? P.S. What happens when you add cheese to the burgers? The cheese melts as the burger transfers energy into the cheese!

Convection: The transfer of energy due to the movement of matter. This happens most efficiently in gases and liquids. Convection occurs when hot matter rises and cool matter sinks due to differences in densities. (C) Copyright all rights reserved

Example: As water is heated in a pot, the warm water at the bottom starts to rise, and the cooler water near the top starts to sink replaceing the rising warm water. This cycle will continue as you heat the water.

(C) Copyright all rights reserved Convection is the transfer of energy due to the movement of matter &safe=images&tbs=sur:fm Watch video

(C) Copyright all rights reserved Convection video discussion: 1.Why did the red food coloring represent hot water? 2.Why did the blue food coloring sink to the bottom? Answer 1. The hot water molecules move faster and spread the food coloring faster. Answer 2. The cold water is denser therefore the molecules move slowly, spreading the food coloring slower.

Watch the Conduction & Convection Video Bill Nye: Heat (22 min.) Bill Nye: Heat (C) Copyright all rights reserved

Review of notes taken from Bill Nye video (C) Copyright all rights reserved Heat moves around the Earth 3 ways, conduction, convection, radiation Heat is energy, all items have heat The metal stick will melt the butter faster More molecules = more heat Hot water expands and is less dense Infrared cameras see thermal radiation Heat radiation is made up of waves Hot air rises, cold air sinks Heat is transferred by one molecule bumping into another molecule

Radiation: The transfer of energy as Electromagnetic Waves. Radiation can transfer energy between objects that are not in direct contact (touching). Other objects besides the Sun can radiate energy as light and heat. (C) Copyright all rights reserved

Examples of Radiation: 1. Microwaves in a microwave oven (C) Copyright all rights reserved A blazing fire at the campsite

Radiation Video Play Play (C) Copyright all rights reserved

(C) Copyright all rights reserved Radiation video discussion: Sun & Earth emit electromagnetic radiation Electromagnetic radiation travels in waves Short wave lengths carry more energy Shorter wave lengths = higher temperature Most of the solar radiation is visible light we see The Sun emits high energy short wave radiation The Earth emits low energy long wave radiation

(C) Copyright all rights reserved So which would you rather be? Conduction Convection Radiation