sciencee Flashcards
central heating system
method of transferring thermal energy from a single, central source through a network of pipes, ducts and vents
conduction
transfer of heat through a solid material. ex: heat transferred through warmer sections of walls to cooler sections
convection
transfer of heat by moving air. ex: warm air rises through roof
radiation
flow of energy in the form of invisible waves
chemical energy
sksksk
geothermal energy
thermal energy deep in earth
insulation
the preventing of heat moving in
local heating system
method of providing thermal energy for one small area only
refrigerant
liquid that evaporates at a low temp, used in a refrigerator
R- value
number that indicates the ability of an insulating material to stop or limit transfer of heat energy
solar array
solar cells in panels that are connected, and then positioned to capture and store the suns energy in batteries
thermal conductivity
ability of a material to transfer heat by conduction
thermostat
device to control temperature; it automatically switches a heating or cooling system on or off
what are the 4 natural sources of thermal energy
the sun, geothermal energy, fire, decay
describe active solar heating and passive solar heating
passive- heated directly by suns waves
active- heating something mechanically with energy
local and central heating systems
central - method of transferring thermal energy from a single, central source through a network of pipes, ducts and vents
local- method of providing thermal energy for one small area only
describe the most to least heat loss in a house
most through walls, through roof, then through floor and gaps, and then windows
describe a thermostat and how it works
a mercury switch sits on a bimetallic strip. when the strip starts heating up, it thermally expands until it gets so hot that it causes the mercury to slide off of the wires to the furnace causing the furnace to turn off. the bimetallic strip cools off and it thermally contracts until the mercury slides back onto the wires turning the furnace on.
passive solar heating
when heating is done directly by sun
describe the parts of a refrigerator
the refrigerant in the storage tank is pumped to the freezer unit. it passes through the freezer unit and the liquid evaporates. it cools as it evaporates so heat transfers warmer air inside the refrigerant to the cooler part. the refrigerator space becomes cooler. now a vapor, it flows through the compressor to the condenser coils. heat transfers out, cools down and becomes a liquid.
