lesson 9

• conduction - transfer of heat through solids by direct contact
• the molecules in an object are always in motion
• when a part of an object is heated, the molecules in that particular part move faster and may collide with the surrounding molecules
• metals - good conductors of heat due to the many free electrons
• these free electrons vibrate and easily collide with other electrons which makes it easier for heat to transfer
• plastics - poor conductors of insulator
• insulator - dont permit heat to pass through them easily
• convection - transfer of heat through liquids and gases
• both air and water move bc of temperature differences
• the movement of a liquid or a gas bc of temp dif creates a circling motion called convection current
• land and sea breeze are caused by convection
• sea breeze - the land warms faster than the sea. the warm air thats above the land rises bc its less dense while the cold air above the sea sinks and blows towards the land
• land breeze - the warmer air above the sea rises while the cold air above the land sinks and blows toward the sea
• temperature regulation - humans and mammals use part of the energy they obtain from the foods to keep the temp constant
• clothes and blankets - form a thermal barrier between the body
• blubber - layer of fat hidden under the skin