Characteristics of the Atmosphere

What is Earth’s atmosphere made of? An atmosphere is a layer of gases that surrounds a planet or moon The air you breathe is made of many different things. Almost 80% of it is nitrogen gas The rest is mostly oxygen, the gas we need to live.

Which two gases make up most of Earth’s atmosphere? Reading Check Which two gases make up most of Earth’s atmosphere?

Where do the gases in the atmosphere come from? Where the gas come from Oxygen Plants give off oxygen as they grow Nitrogen Nitrogen is given off when dead plants and animals decay Water Vapor Liquid water evaporates and become water vapor Plants give off water vapor as they grow. Water vapor comes out of the Earth during volcanic eruptions Carbon dioxide Carbon dioxide comes out of the Earth during volcanic eruptions When animals breathe, they give off carbon dioxide. Carbon dioxide is off when we burn things that were once plant or animal material.

Name two gases that volcanoes contribute to the atmosphere. Take a Look: Identify Name two gases that volcanoes contribute to the atmosphere.

Air Pressure- is how much air above you weighs. The higher you go, the lower the air pressure gets.

4 Main Layers of the Atmosphere Troposphere Stratosphere Mesosphere Thermosphere

Troposphere The layer of the atmosphere that we live in. Almost 90% of the gases in the atmosphere is here The higher you move into the troposphere, both air temperature and air pressure decrease

Stratosphere Stratosphere = layers Temperature increases Temperature increases because of a gas called ozone. Ozone layer protects living things by absorbing harmful ultraviolet energy

Reading Check Why is ozone in the stratosphere important for living things.

Mesosphere Is above the ozone layer Temperature drops again

Thermosphere Uppermost layer of the atmosphere Temperature begins to rise again Thermo= heat

Ionosphere Auroras are curtains and ribbons of shimmering colored lights. Please google auroras now to see what they really look like.

At what altitude does the mesosphere end and the thermosphere begin?

Answer the questions below by using the previous slide. At what altitude does the mesosphere end and the thermosphere begin? Where auroras occur? What layer of the atmosphere will you find: Space craft Hot air balloon People or animal Meteors Satellites Commercial aircraft Parachute jumper Supersonic plane