Atmosphere Flashcards
What makes up the atmosphere?
78.08% nitrogen, 20.95%oxygen, and 0.93% argon.
define the atmosphere
the layer of air surrounding the earth. It is made up of gases that are necessary for acting as a shield and blocking out UV rays. It also ensures a stable climate by retaining heat
why does air exert pressure?
it contains particles that are colliding with one another. These collisions determine the atmospheric pressure. More collisions = more pressure
what affects atmospheric pressure?
-it depends on the height of a place above sea level and decreases with an increase in altitude.
At higher altitudes, the density and temperature of the air are lower, so the number of collisions decreases
-It also depends on temperature. Hotter = less pressure. Colder = more pressure. If it’s hot the particles move away from each other so it rises to higher altitudes. If it’s cold, the air is more dense thus sinks to lower altitudes
what describes air movement?
atmospheric circulation
how does air move around the world?
it rises above hot regions at the equator and moves towards the poles (cold region)…which causes it to sink. As the earth rotates, the dense air then makes it’s way towards the equator again.
what is the Coriolis effect
air masses should move in a straight line but the rotation of the earth changes their trajectories
from which direction does pollution come from?
the west
what are prevailing winds?
major atmospheric currents that blow in a given direction according to atmospheric circulation
from top to bottom, name all the prevailing winds
polar easterlies
westerlies
trade winds
what substances contaminate the atmosphere?
fossil fuels
metals like mercury, arsenic and lead
dust
which substances play a role in acid rain
SO2 and NOx
what is the ozone layer and what is it composed of
a chemical filter that absorbs UV rays it’s composed of 3 oxygen atoms
when is ozone beneficial and harmful to us?
it’s beneficial at high altitudes but it’s harmful at lower altitudes. If it’s at the bottom, it chemically combines with sulfur dioxide or nitrogen dioxide which creates smog
what is smog a mixture of
fog, smoke, and other air pollutants
