Embedded Files
Title: What Goes Up Must Come Down: The Water Cycle
Principle(s) Investigated: How water changes from one state to another – The Water Cycle
o MS-ESS2-4. Develop a model to describe the cycling of water through Earth’s systems driven by energy from the sun and the force of gravity.
· Water continually cycles among land, ocean, and atmosphere via transpiration, evaporation, condensation, and crystallization, and precipitation, as well as downhill, flows on land. (MS-ESS2-4)
· Global movements of water and its changes in form are propelled by sunlight and gravity. (MS-ESS2-4)
Science and Engineering Practices:
· Developing and Using Models Modeling in 6–8 builds on K–5 experiences and progresses to developing, using, and revising models to describe, test, and predict more abstract phenomena and design systems. · Develop a model to describe unobservable mechanisms. (MS-ESS2-4)
Crosscutting Concepts
· Energy and Matter within a natural or designed system, the transfer of energy drives the motion and/or cycling of matter. (MS-ESS2-4)
Materials:
o Two glasses
o A pitcher of water
o A mixture of salt and sand
o A large bowl
o A smaller bowl
o Cellophane
o A few small rocks
o USGS Interactive water cycle map: https://water.usgs.gov/edu/watercycle-kids-adv.html
o USGS Stages of water cycle diagram
o USGS Water in you https://water.usgs.gov/edu/propertyyou.html
o USGS How much water is there on, in, and above the earth? https://water.usgs.gov/edu/earthhowmuch.html
Procedure:
Engage:
-The teacher begins class with two empty glasses, a pitcher of water and container of salt & sand.
-Teacher fills both glasses filled with water and then invite a volunteer to drink from one glass.
-Teacher asks, “What does this taste like?”
-Student response, “Water”
-Teacher, “That is correct it is a glass of pure water.”
-The teacher invites another student to drink out of the other glass. But before the student has a chance to, Teacher dramatically pours the salt and sand mixture out into the glass!
-Teacher asks the student if they still want to partake in a drink?
-Student response, “No”
-Teacher, “Ok, what would it take for me get you to drink the water out of this glass.
-Student, “An A.”
-Teacher, “Haha, well you can earn an A if after this investigation by explaining how we can safely drink this same water.”
Student prior knowledge:
My students have a basic knowledge of the concept of the properties of water. (liquid, solid, gas) Which we will touch on first. They also have knowledge of where water can be stored.
Explore/Explain:
“We know when you are thirsty you go to the kitchen turn on the faucet to fill a glass with water. If you want the water to be cool, you open the freezer and grab some ice cubes. If you want hot water for tea or hot chocolate you fill a pot with water set in above fire until it starts boiling.”
In nature water is always change, it is in fact always moving. From the rivers, and stream to the ocean, up in the sky and back down around to the ground. Water and the movement of water are vital to all life on earth. In order for water to be everywhere, it has to be constantly be moving.
How much water is there on (and in) the Earth? Here are some numbers you can think about:
· If all of Earth's water (oceans, icecaps and glaciers, lakes, rivers, groundwater, and water in the atmosphere was put into a sphere, then the diameter of that water ball would be about 860 miles (about 1,385 kilometers), a bit more than the distance between Salt Lake City, Utah to Topeka, Kansas. The volume of all water would be about 332.5 million cubic miles (mi3), or 1,386 million cubic kilometers (km3). A cubic mile of water equals more than 1.1 trillion gallons. A cubic kilometer of water equals about 264 billion gallons.
· About 3,100 mi3 (12,900 km3) of water, mostly in the form of water vapor, is in the atmosphere at any one time. If it all fell as precipitation at once, the Earth would be covered with only about 1 inch of water.
· The 48 contiguous (lower 48 states) the United States receives a total volume of about 4 mi3 (17.7 km3) of precipitation each day.
· Each day, 280 mi3 (1,170 km3) of water evaporate or transpire into the atmosphere.
· If all of the world's water was poured on the contiguous United States, it would cover the land to a depth of about 107 miles (145 kilometers).
· Of the freshwater on Earth much more is stored in the ground that is available in lakes and rivers. More than 2,000,000 mi3(8,400,000 km3) of freshwater is stored in the Earth, most within one-half mile of the surface. But, if you really want to find freshwater, most are stored in the 7,000,000 mi3 (29,200,000 km3) of water found in glaciers and icecaps, mainly in the polar regions and in Greenland. *
Resource: (https://water.usgs.gov/edu/earthhowmuch.html - U.S. Geological Survey - How much water is there on, in, and above the Earth?)
In today’s lesson will explore the different ways that water moves through the water cycle.
“Tell me one of the ways water moves from one state and place to another in nature?”
Water from the ocean becomes frozen ice on top of a mountain, water from a lake will go underground and be absorbed by at tree. We are going to explore this concept further with a quick video demonstration.
National Science Foundation: video on The water cycle: https://www.youtube.com/watch?v=al-do-HGuIk
Pretty interesting stuff. Let’s dive deeper into the explanation. Students on your computer please go to the website link below, it will bring you to an interactive diagram of the water cycle:
As a group, take 10 mins exploring the diagram, click and read the different states of the water cycle, then log on to the class google doc and fill in the table next to your name, an example is provided for clarification.
Class Google Doc ---> Water Cycle Diagram
Extend/Elaborate:
Now that we have an understanding of the water cycle, let's figure out how we’re going to make this water drinkable. In this investigation, we will be creating a small-scale version of the water cycle. One of the amazing benefits of the water cycle is its ability to purify our water supply. We are going to use these same principles to purify our water today.
Teacher assigns partners, please come get materials, one for each group. The first thing we are going to do is pour our salt & sand into the bottom of our large bowl. Second, we will fill our large bowl about a quarter full. This represents the ocean water. In the middle of our large bowl place the small bowl down. This represents a lake. Grab the cellophane and create a tight seal on top. This represents the atmosphere. Now let’s carry our bowls outside and set it in the sun. Lastly, place a stone in the middle of the cellophane directly over the small bowl. Now we wait.
Water Cycle Model
Resource: (http://shoalwater.nsw.gov.au/Community/Tapstar/Kids/Fun-with-Water)
Explanation:
As the sun rays hit the bowl, the water inside will start to heat up, causing the water to transform (evaporate) into water vapor. The evaporation will reach the atmosphere (cellophane) slowly turning into condensation. As the condensation builds and becomes heavy and when it cools off it will begin to fall back down to the surface as precipitation. While most of the water will land back into the ocean becoming contaminated again, some fresh water will begin to form in the “lake”. This clarified water replenishes our water supply making it cleaner for consumption.
Assessment:
Create a 2D model of the water cycle (labeling Precipitation, Condensation, Evaporation and Runoff). Upload your 2D model drawing of a water-cycle using CamScanner into Water Cycle Folder
Questions & Answers:
- How could the process of evaporation be used to purify water? Why might this not be effective on a large scale?
Evaporation separates the water molecules from impurities that are in the water source, collecting the water as it falls back down creates purer water. In order to collect enough water sustainably for consumption a lot of time and energy must be spent.
- Which step in the water cycle is most important for humans? Why? Is there a way we could manipulate the water cycle to get more fresh water for humans to drink?
Evaporation and infiltration benefit humans by purifying water. When water evaporates, the pollutants and sediments in it are left behind. Even aquatic life needs water purified, as salt water must be within certain pH and saline ranges. As water undergoes infiltration, the ground purifies it of pollutants and contaminants.
Water management methods have attempted to control and manipulate the hydrological cycle to best fit human needs with dams, diversions, and reservoirs. While these solutions help provide water, and for many people, they have also severely disrupted the functioning of aquatic ecosystems.
- If the water cycle never ends, why is it that we experience water shortages?
Water shortages may be caused by climate change, such as altered weather patterns including droughts or floods, increased pollution, and increased human demand and overuse of water. Water shortage can be driven by two converging phenomena: growing freshwater use and depletion of usable freshwater resources.
Applications to Everyday Life:
Water that builds on the outside of a sealed cold beverage
The drops come from the surrounding atmosphere. Because colder air causes condensation at a higher rate than warm air, water vapor contained in the surrounding warm air condenses when it comes in contact with a colder beverage.
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A Lake in the middle of nowhere forms overnight
Water trapped below the earth surface is constantly moving trying to find a way back to the surface. When the ground opens up, the water rushes up to the surface creating what appears to be a lake overnight.
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Sinkholes
Sinkholes capture drainage and can hold it in large limestone caves. These caves may drain into tributaries of larger rivers, they are a part of the water cycle.
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