Water Cycle grade 8

What Is The Water Cycle?

The water cycle or the hydrologic cycle, that involves continuous circulation/movement of the water in the air, on the surface and below the Earth.

Why Is The Water Cycle Important ?

The water cycle is important because it ensures the availability of water for living organisms, and regulates the weather patterns. If there wasn't a water cycle we would run out of clean water, which is the essential needs of living organisms and human beings.

Why Is The Water Cycle Important?

What Are The Processes That Occur In The Water Cycle ?

The Processes In The Water Cycle

• Evaporation
• Condensation
• Sublimation
• Precipitation
• Transpiration
• Runoff
• Infiltration

Evaporation

Evaporation is the first step in the water cycle. It is where water at the surface turns into water vapor; water takes in heat energy from the sun and turns into vapor. As water evaporates it reduces the temperature of the bodies of water.The main source of water evaporation are the large bodies of water such are oceans, lakes, rivers, seas etc.

Evaporation

Condensation

Condensation is the transformation of water vapor into tiny particles of liquid water/ice in the air creating clouds and fog. This works because the temperature of the high altitude is low. An example of condensation is the dew forming in the morning, on leaves and grass because the warmer air deposits water molecules on the cool leaves and grass.

Condensation

Sublimation

Sublimation is when ice directly converts into water vapor, without going through the stage of changing into water/liquid. This is increased when the temperature is low or the pressure is high. The ice sheets from the North pole and South pole and the ice caps on the mountains are the main source for sublimation. Sublimation is a slower process than evaporation. An example of sublimation is when dry ice or solid carbon dioxide changes to gas/vapor.

Sublimation

Precipitation

The clouds which are condensed with water vapor, pour down due to changes in temperature or wind. This happens because the smaller water droplets combine to make bigger droplets (e.x., rain). This occurs when air is unable to hold any more water. At a high altitude the temperature is low, in which the water droplets lose their heat. If the temperature is below 0 degrees the water droplets fall as snow.

Precipitation

Transpiration

While the water precipitates, some of it is absorbed by the soil. This water enters into the process of transpiration. Evaporation and transpiration are similar process, but this process is where liquid water is turned into vapor by pants. In this process water is absorbed by the roots of the plants and push it towards the leaves for photosynthesis. The extra water is moved through small openings of the leaves, which eventually turn in to vapor

Runoff

Runoff is a process where water runs over the surface of the Earth. Runoffs could be in any form of precipitation, such as rain. As the water is runs over the ground, the water takes over the place of top soil and moves the minerals along with the stream. When runoffs happen this creates small water routes which eventually leads to rivers, then ends up in lakes, oceans, and seas.

Runoff

Infiltration

The last process of the water cycle is "infiltration"; this is where the precipitated water does not runoff but is absorbed by plants or gets evaporated. Due to this the water seeps down into the underground water table and increases the level. In this the water is drinkable/clean. A good way to remember what infiltration is when the water gets filtered for it to be drinkable.

Infiltration

Resources

• Deutsche Welle. “Are We Running out of Fresh Water?: DW: 29.08.2017.” DW.COM, https://www.dw.com/en/are-we-running-out-of-fresh-water/a-40241057.
• Frozen Carbon Dioxide (Dry Ice) Sublimates Directly into a Vapor., https://www.usgs.gov/media/images/frozen-carbon-dioxide-dry-ice-sublimates-directly-a-vapor.
• “Morning, Dew Drops on the Grass.” VideoHive, 24 May 2018, https://videohive.net/item/morning-dew-drops-on-the-grass/21911933.
• NASA, NASA, https://pmm.nasa.gov/education/water-cycle.
• NASA, NASA, https://pmm.nasa.gov/resources/faq/why-are-water-cycle-processes-important.
• Nationwide, SARE. “Infiltration vs. Runoff.” SARE, https://www.sare.org/Learning-Center/Books/Building-Soils-for-Better-Crops-3rd-Edition/Text-Version/Soil-Particles-Water-and-Air/Infiltration-vs.-Runoff.
• payment, One-time, et al. “Diagram Showing Transpiration Plant Vector Image on VectorStock.” VectorStock, https://www.vectorstock.com/royalty-free-vector/diagram-showing-transpiration-plant-vector-27144356.
• payment, One-time, et al. “Diagram Showing Transpiration Plant Vector Image on VectorStock.” VectorStock, https://www.vectorstock.com/royalty-free-vector/diagram-showing-transpiration-plant-vector-27144356.
• “The Hydrologic Cycle (Water Cycle).” H2O Distributors, Inc, https://www.h2odistributors.com/pages/info/info-water-cycle.asp.
• “THE WATER CYCLE: A GUIDE FOR STUDENTS.” The Water Cycle: A Guide For Student APEC Water, https://www.freedrinkingwater.com/resource-water-cycle-student-guide.htm.
• “Types of Precipitation.” Teachers Pay Teachers, https://www.teacherspayteachers.com/Product/Types-of-Precipitation-3470213.
• “Weather Questions & Answers.” Weather Questions, https://weatherstreet.com/weatherquestions/What_is_water_vapor.htm.
• “What Is Runoff.” County of Santa Barbara, https://countyofsb.org/pwd/sbpcw/runoff.sbc.