Water Cycle and the Atmosphere

Where is water on Earth? Reservoirs- protected artificial or natural lakes Groundwater- water that collects underground

Water Cycle The continuous movement of water from the atmosphere to the earth’s surface and back to the atmosphere again. Aka: hydrologic cycle Parts of the Water Cycle Evaporation Transpiration Runoff Ground Water Condensation Precipitation

Parts of the Water Cycle Evaporation: liquid water changes into water vapor Transpiration: plants give off water vapor into the atmosphere Runoff: flows over land into rivers Ground Water: water that soaks deep into the soil and rock underground Condensation: water vapor cools into tiny liquid water droplets (clouds) Precipitation : water falls from clouds to the earth’s surface (rain, snow, sleet, and hail) Aquifer: Underground area of sediment and rocks that hold groundwater

What's in Earth's atmosphere? This protective layer exists around Earth because our planet has just the right balance of size and distance from the sun.

The Atmosphere Earth’s atmosphere is a layer of gases surrounding the planet, protecting and sustaining life. It insulates us so that we don’t freeze at night. Its ozone layer protects us from the sun’s ultraviolet rays.

Atmospheric pressure Atmospheric pressure is a measurement of the force of air molecules in the atmosphere at a given altitude. The pressure of the atmosphere changes as you rise above sea level.

Pressure changes with altitude

Parts of an Aneroid Barometer

Layers of the Atmosphere Four Layers Thermosphere Mesosphere Stratosphere Troposphere* The atmosphere is divided into layers based on temperature changes. We live in the troposphere which is 0 to 11 kilometers above Earth's surface.

Layers of the Atmosphere The four layers of the atmosphere include: the troposphere, where we live; the stratosphere, which contains the ozone layer; the mesosphere, where meteors burn; and the thermosphere, where satellites orbit Earth.

Energy in the Atmosphere Our sun converts 5 million tons of its own mass into energy every second. This process involves nuclear fusion. Even though Earth intercepts only a tiny fraction of the radiation broadcast by the sun into space, this radiation provides most of Earth’s thermal energy.

Greenhouse effect There are molecules in the atmosphere that act like the pebbles in the bucket. They make it take longer for the infrared radiation to escape back into space compared to bucket with no pebbles.

Greenhouse effect Adding greenhouse gases to the atmosphere is like adding more pebbles to the bucket. It takes longer for radiation to escape from the atmosphere, so Earth’s average temperature rises.