Presentation on theme: "What is HEAT What Are Its Properties?. Heat Draw a teakettle of water heating on a burner. Draw an arrow pointing to the area where the water is the hottest."— Presentation transcript:
What is HEAT What Are Its Properties?
Heat Draw a teakettle of water heating on a burner. Draw an arrow pointing to the area where the water is the hottest. Draw an arrow pointing to the area where the water is the coolest. Predict the direction in which the hottest water is moving. Predict the direction in which the coolest water is moving.
HEAT - Definition Heat is the MOVEMENT of thermal energy Heat ALWAYS moves from Warmest to Coldest Why? It is always HIGHER Energy – to – LOWER Energy There is no scientific definition of ‘Coldness’ Cold is a relative term
TYPES of HEAT RADIATION – movement of energy through electromagnetic energy (light) Like the sun shining on your skin CONDUCTION – Heat moving through an object, passed from atom-to-atom and molecule to molecule Like a hot metal spoon in boiling water CONVECTION – Heat being carried through rising and falling currents of a liquid or gas Like wind currents or steam rising
TYPES of HEAT RADIATION – How do you stop it? Good - Shade Best (mirrors) CONDUCTION – How do you stop it? Good - Use an insulating material (one that doesn’t conduct) Best – remove all material (vacuum) CONVECTION – How do you stop it? Good – put a lid on it Better – internal barriers Best –fill it to the top
CONDUCTORS A Substance that passes HEAT easily Hard Shiny Metallic Dense Examples: Metals Glass Some plastics
INSULATORS A Substance that DOES NOT pass Heat easily. Properties: Not dense Not-Metallic Soft Examples: Cotton Air Fiberglass Cloth Plastics Vacuum
Convection Radiation Conduction is the transfer of Thermal energy by