Cycles of Matter Chapter 20, Lesson 2

What is the Water Cycle? The process in which water continually cycles from Earth to its atmosphere and then back again There are three processes involved in the water cycle: Evaporation Condensation Precipitation

Particles in Matter ALL MATTER IS MADE UP OF PARTICLES. Solid Liquid particles are closely packed usually in a regular pattern particles cannot move/slide past one another Liquid particles can move/slide past one another still close together particles can move/slide past one another; Gas Particles move past each other freely at high speeds

Solid, Liquid, Gas

When Energy is Added

Evaporation During the water cycle, the sun provides the energy to turn liquid water into a gas – EVAPORATION In the case of the water cycle, this gas is called water vapor. It is important to remember that water vapor is an invisible gas; if you can see it, it is NOT water vapor!

From which water sources does the water vapor come? OCEANS LAKES, RIVERS, STREAMS, ETC. TRANSPIRATION AND EXHALATION Transpiration – the release of water vapor from the stems and leaves of plants Exhalation – when animals exhale (breathe out) water vapor travels out of the body and into the atmosphere

Condensation The higher you go in the atmosphere, the temperatures become cooler and cooler As water vapor rises, the water vapor cools and the particles slow down When particles slow down, the gas turns back into a liquid – CONDENSATION The water collects on little bits of dust and forms clouds. Depending on altitude, clouds can be made of drops of water or ice

Precipitation The process in which water from clouds falls back to earth Can take form of rain, sleet, hail, snow Happens when so many droplets of water or ice become too heavy to stay in the clouds and so, falls to Earth Precipitation becomes part of the water cycle once again.