Earth Science Chapter 16
what happens to sunlight as it passes through earth's atmosphere?
Half is absorbed in ozone by clouds (water vapor- acts as mirror), gases (carbon dioxide), ozone. Dust and gases reflect the light (called "scattering") or reflected by surface (water) back into atmosphere (see diagram page 544) Half is absorbed by Earth's surface, heating land and water.
thermal energy
TOTAL energy of motion in the particles of a substance (hot tea in pot has more thermal energy than hot tea in cup because there are MORE particles in POT)
why does sky look red at sunset
at sunrise and sunset, the light passes through thicker atmosphere and blue light is scattered more, so mostly red and orange light is visible.
visible light
colors you see in a rainbow (ROYGBIV) RED = LONGEST WAVE; VIOLET = shortest wave
what causes wind
differences in air pressure caused by differences in heating of the atmosphere (cooler air flows under hotter air)
radiation
direct transfer of energy by electromagnetic waves (most heat you feel from sun is infrared radiation- invisible but feels hot)
conduction
direct transfer of heat from one substance to another that it is touching (hot sand burns your feet) the closer the molecules, the better conduction (solids conduct better than liquids or gas)
why does daytime sky look blue?
gas molecules scatter short wavelengths of light (blue and violet) more than long (red and orange) so the sky looks blue.
infraRED radiation
has waves LONGER than RED light. Is NOT VISIBLE, but is felt as HEAT
convection currents
heavier (cooler, denser) air sinks while lighter, warmer air rises. The up and down movements of air form currents.
Electromagnetic waves
how the sun's energy travels to earth (measured in wavelengths or distance between waves)
ultraVIOLET radiation
invisible form of energy with wavelengths SHORTER than VIOLET light. causes sunburns, skin cancer and eye damage.
sea breeze
local wind that blows from an ocean or lake (caused by unequal heating- land warms up faster than ocean so air over land becomes warmer than air over ocean, causing warm air over land to rise and cool air from water flows in under warm air.
anemometer
measures wind speed.
three ways heat is transferred
radiation, conduction, convection (all three heat the TROPOSPHERE)
wind vane
tells us wind DIRECTION (north wind blows OUT OF the NORTH toward the south)
temperature
the AVERAGE amount of energy of motion of each particle of a substance. (how hot or cold)
radiation
the direct transfer of energy by electromagnetic waves
wind
the horizontal movement of air from an area of high pressure to an area of lower pressure.
wind chill factor
the increased cooling a wind causes the actual temperature to feel colder
heat
the transfer of THERMAL energy from a hotter object to a cooler one.
convection
the transfer of heat by the movement of a FLUID
thermometer
thin glass tube with a bulb on one end that contains liquid, usual mercury or colored alcohol (used for measuring temperature. (heat causes liquid to expand and rise in tube)
degrees
unit of measurement of temperature
celsius scale
used by scientists. freezing of water on celsius is 0 degrees. Boiling is 100 degrees.
what three types of energy do we receive from the sun?
visible light, infrared radiation and ultraviolet light.
fahrenheit scale
weather reports use fahrenheit. freezing on fahrenheit is 32 degrees. Boiling is 212 degrees.
greenhouse effect
when earth's surface is heated by sunlight, it radiates the energy back into the atmosphere (infrared radiation) and this energy cannot travel back to space so it is absorbed by gases and water vapor in atmosphere, forming a "blanket" around earth, holding heat in the atmosphere.
