Download
1 / 21
240 likes | 561 Vues
Water on Earth S6E3. a Explain that a large portion of the Earth’s surface is water, consisting of oceans, rivers, lakes, underground water and ice S6E3. B Relate various atmospheric conditions to stages of the water cycle. Water on Earth.
E N D
Water on EarthS6E3. a Explain that a large portion of the Earth’s surface is water, consisting of oceans, rivers, lakes, underground water and iceS6E3. B Relate various atmospheric conditions to stages of the water cycle.
Water on Earth • Earth is made up of 70 percent Water. This is both salt and fresh water. • From space an astronaut would see mainly water if he/she was looking at earth from space. • Its like having a dollar. 70 cents of it is water and only 30 cents is land. Together they equal 100 cent or a dollar. Together all the water and land equal all of earth’s surface.
Water on Earth • So of the 70 percent water on earth, we have to split that up into fresh and salt water. • Salt water accounts for 99.7% of all the water on Earth • Fresh water accounts for only .03% of the water on Earth. • Where is all the salt water? Salt water is in the oceans, seas and atmosphere(evaporation). • Where is all the fresh water? Fresh water is in rivers, lakes, streams, springs, Polar ice caps(frozen) and water table.
Polar Ice Caps (fresh water) • The majority of the fresh water that earth has is frozen in the polar ice caps. • Variations in earth’s climate causes some to melt or more to freeze. • If the polar ice caps change then we know there has been a change in the climate on earth.
The water cycle • 5 steps of the water cycle • Precipitation • Percolation • Runoff • Evaporation • Condensation Each work together to create what we call the water cycle.
What makes the water cycle run? • The sun is the major energy source that helps the water cycle function. • Most of all water that is involved in the water cycle comes from the oceans because that’s where 99.7 % of our water is.
Evaporation • The sun causes water to evaporate changing it from a liquid to a gas and that water fills the air above it. The more water that evaporates the more water that is in the air. • When the air around us contains water vapor we call that Humidity. • Humidity is the amount of water in the air around us. • The air and water are then circulated up by what we call convection. • Convection is the circulation of air to a higher elevation.
Condensation • Condensation happens when air cools and condenses and the water vapor in the air becomes water droplets. • For example…. If you fill a glass full of ice water and sit it outside you will notice that the glass begins to form drops of water on the outside of the glass. This is condensation. • What happens is when warm air meets the cool glass then the warm becomes cool and has to release the water vapor that it is holding. • The temperature at which warm air condenses is called it dew point.
Condensation • So from the water that has evaporated from the ocean or lakes, convection carries it up in the earths atmosphere where it becomes cool and then condenses to form clouds. • Clouds are formed by condensation of warm air from evaporation. • Clouds are millions of tiny droplets of water.
Precipitation • Precipitation is rain, sleet, snow or hail from a cloud that falls back to earth and returns to the ocean or nearest body of water. • Precipitation is formed when clouds become to full of water vapor or droplets and then releases it in the form of rain, sleet, snow or hail. • Hail is more complicated. As water droplet build up and become heavy, updrafts can send it up higher into the cloud where it is much colder. It freezes and becomes to heavy.
Runoff • Runoff is when precipitation hits the ground and then streams back to a large body of water. • Most water returns to large bodies of water by precipitation but a small amount returns by runoff. • Runoff causes erosion and damage to the land and sometimes your private property.
Percolation • Percolation is when precipitation filters through the ground and returns to the water table. • The water table is a body of water under the surface in which our water for irrigation for farms and water for our houses comes from. • Percolation allows plants and animals to get water needed to grow.
