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Characteristics of Materials. (Solar) Energy is absorbed differently in materials depending on certain characteristics. Absorbing Energy Light materials are good reflectors Dark colored materials are good absorbers. You wear different clothes based on the weather. HOT COLD.
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Characteristics of Materials (Solar) Energy is absorbed differently in materials depending on certain characteristics. Absorbing Energy • Light materials are good reflectors • Dark colored materials are good absorbers
Material Texture • Rough material is a good absorber • Smooth material is a good reflector
ALSO, EVERY MATERIAL HAS… …A SPECIFIC PROPERTY THAT ALLOWS IT TO HEAT UP OR COOL DOWN AT IT’S OWN PACE. WE SCIENTISTS CALL IT: SPECIFIC HEAT
SPECIFIC HEAT • SPECIFIC HEAT – THE AMOUNT OF ENERGY REQUIRED TO HEAT ONE GRAM OF A SUBSTANCE ONE DEGREE CELSIUS. • MEASURED IN: JOULES/GRAM*DEGREE CELSIUS!
SPECIFIC HEAT Specific Heats of Common Materials
WATER • LIQUID WATER HAS THE HIGHEST SPECIFIC HEAT OF ANY SUBSTANCE ON EARTH: • 4.18 Joule/GRAM*DEGREE CELSIUS
HUH?!? Let’s Review… • The higher the number, the longerit takes to heat up and cool down. • The lower the number, the faster it takes to heat up and cool down.
Specific Heats of Common Materials • Which substance has the highest specific heat? • Which substance has the lowest? • Which one will heat up and cool down fastest?
Temperature • Temperature - measurement of the average kinetic energy of molecules • The higher the temperature the faster the molecules are moving & the more kinetic energy it has.
Thermometer • As the liquid is heated up, the molecules expand and rises in the tube • The opposite happens when the liquid gets cooler
The Three Scales (ESRT P.13) • Celsius = metric system • Water freezes at 0°C and boils at 100°C • Kelvin = used by scientists • You convert Celsius to Kelvin by adding 273 • Example 20°C =293K • The lowest reading of temperature is on the Kelvin scale • This is called absolute zero