Atmosphere Study Guide

atmosphere
thin layer or envelope of gases that surrounds Earth; traps energy from the sun which allows water to be a liquid; plants and animals need the gases to survive
nitrogen
most abundant gas in the atmosphere
ozone
a form of oxygen with three oxygen atoms in each molecule
water vapor
water in the form of a gas; it makes air not dry
mass, density, and pressure
three properties of air
aneroid barometer
instrument used to measure air pressure without liquid
smog
created by smoke and fog
troposphere
lowest and shallowest layer of the atmosphere; layer where weather occurs and people live
stratosphere
contains ozone and protects living things from ultraviolet radiation from the sun
thermosphere
divided into two layers, the ionosphere and the exosphere; outermost layer of the Earth’s atmosphere; has no definite outer limit
mesophere
layer of atmosphere that protects Earth’s surface from being hit by most meteroids
pollutants
harmful substances in the air, water, or soil
burning fossil fuels
creates most most air pollution
photochemical smog
sunlight on pollutants causes a brownish mixture of ozone and other pollutants
altitude
elevation, or the distance above sea level; air pressure decreases as altitude increases (air becomes thinner)
air pressure
weight of a column of air pushing down on an area; doesn’t crush us because air pushes in all directions; units measured in millibars and inches of mercury
air is about 78% nitrogen and 21% oxygen
at sea level; at top of mountains; in cities and surrounding suburbs
troposphere, stratosphere, mesophere, thermosphere
four main layers in our atmosphere from Earth to space; divided by scientists based on changes in temperature
weather
condition of the Earth’s atmosphere at a particular time and place
acid rain
contains more acid than normal; rain is naturally slightly acidic