Characteristics of the Atmosphere • Atmosphere is a mixture of gases that surrounds Earth. • Contains oxygen O2 that you need to breathe • Protects you from the sun’s damaging rays
Composition of the Atmosphere • Nitrogen – makes up 78% of the atmosphere • Oxygen – makes up only 21% • Argon , Carbon Dioxide, Water Vapor, & Other Gases – makes up remaining 1% • Atmosphere also contains dust, volcanic ash, sea salt, dirt and smoke
Air Pressure • The atmosphere is held around the Earth by gravity. • Gravity pulls gas molecules in the atmosphere toward the Earth’s surface, causing air pressure. • Air pressure is the measure of the force with which air molecules push on a surface.
Troposphere : The layer in which we live and where weather occurs. • Stratosphere : Home of the ozone layer ( protects life on Earth by absorbing harmful ultraviolet rays). • Mesosphere : The middle layer and is the coldest layer. • Thermosphere : The hottest layer. It contains the Ionosphere home of the Auroras.
Ionosphere • Is located in the Thermosphere where there are electrically charged particles called ions • These ions produce colorful lights called the Northern and Southern Lights. These lights are also known as Auroras. • The ionosphere allows radio waves to travel across the country to another city.
Exosphere – The outermost layer of the atmosphere. • The Troposphere • Screaming Stratosphere • Monster Mesosphere • Terrorized Thermosphere • Everyone Exosphere