18.104.22.168 The Water Cycle
Identify where water collects on Earth, including atmosphere, ground and surface water, and describe how water moves through the Earth system using the processes of evaporation, condensation and precipitation.
MN Standard in Lay Terms
The water cycle is an important (essential) multi-step process that allows fresh water to be available for everyday life (Koch, et. al).
- The concepts of the water cycle are based on the beginning understanding of states of matter (water) and the behavior of matter (water) in different states
- water is an essential resource to daily life, the water cycle is an important (essential) multi step process that allows fresh water to be available for everyday life (Koch)
- Water is a limited resource
- When liquid water disappears it turns into a gas (vapor) in the air and can reappear as a liquid when cooled, or as a solid if cooled below the freezing water. (Benchmarks for Science Literacy p. 68)
- Clouds and fog are made of tiny water droplets (Benchmarksfor Science Literacy p68)
MN Standard Benchmarks
22.214.171.124.1 Identify where water collects on Earth, including atmosphere, ground, and surface water, and describe how water moves through the earth system using the processes of evaporation, condensation and precipitation.
There is a correlation between this benchmark and other 4th grade science standards including 126.96.36.199.2
- NSES Standards:
(this is a grade 5-8 standard) Water, which covers the majority of the earth's surface, circulates through the crust, oceans, and atmosphere in what is known as the "water cycle." Water evaporates from the earth's surface, rises and cools as it moves to higher elevations, condenses as rain or snow, and falls to the surface where it collects in lakes, oceans, soil, and in rocks underground.
- AAAS Atlas:
The student will understand that when liquid water disappears it turns into a gas (vapor) in the air and can reappear as a liquid when coled, or as a solid if cooled below the freezing point of water. Clouds and fog are made of tiny droplets of water
- Benchmarks of Science Literacy:
The student will understand that when liquid water disappears it turns into a gas (vapor) in the air and can reappear as a liquid when cooled, or as a solid if cooled below the freezing point of water. Clouds and fog are made of tiny droplets of water
- Common Core Standards
188.8.131.52 Describe the overall structure (e.g., chronology, comparison, cause/effect, problem/solution) of events, ideas, concepts, or information in a text or part of a text.
184.108.40.206 Interpret information presented visually, orally, or quantitatively (e.g., in charts, graphs, diagrams, time lines, animations, or interactive elements on Web pages) and explain how the information contributes to an understanding of the text in which it appears.
220.127.116.11 Use tables, bar graphs, time lines and Venn diagrams to display data sets. The data may include fractions or decimals. Understand that spreadsheet tables and graphs can be used to display data.
- The actual water cycle and water moving in and out of the atmosphere to have an effect on climate is not fully understood until grades 6-8 (benchmarks p69)
- mechanisms of evaporation and condensation are not understood until early high school (Benchmarks p 336)
- Grade 4 misconceptions- when water evaporates it disappears or exists in another place but is still a liquid (from Benchmarks pg 336)
- Grade 4 misconception- water vapor does not immediately go up to the clouds or sun the way it is often depicted in pictures (Keeley, P. Uncovering Student Ideas in Science Vol.1)
Willie the Hamster
Ms. W. encourages students to engage in an investigation initiated by a question that signals student interest. The context for the investigation is one familiar to the students-a pet in the classroom. She teaches some of the important aspects of inquiry by asking the students to consider alternative explanations, to look at the evidence, and to design a simple investigation to test a hypothesis. Ms. W. has planned the science classes carefully, but changes her plans to respond to student interests, knowing the goals for the school science program and shaping the activities to be consistent with those goals. She understands what is developmentally appropriate for students of this age-she chooses not to launch into an abstract explanation of evaporation. She has a classroom with the resources she needs for the students to engage in an inquiry activity.
George is annoyed. There was plenty of water in the watering can when he left it on the windowsill on Friday. Now the can is almost empty, and he won't have time to go the restroom and fill it so that he can water the plants before science class starts. As soon as Ms. W. begins science class, George raises his hand to complain about the disappearance of the water. "Who used the water?" he asks. "Did someone drink it? Did someone spill it?" None of the students in the class touched the watering can, and Ms. W asks what the students think happened to the water.
Marie has an idea. If none of the children took the water, then it must be that Willie, their pet hamster, is leaving his cage at night and drinking the water. The class decides to test Marie's idea by covering the watering can so that Willie cannot drink the water. The children implement their investigation, and the next morning observe that the water level has not dropped. The children now have proof that their explanation is correct. Ms. W. asks the class to consider alternative explanations consistent with their observations. Are they sure that Willie is getting out of his cage at night? The children are quite certain that he is.
"How can you be sure?" asks Ms. W. The children devise an ingenious plan to convince her that Willie is getting out of the cage. They place his cage in the middle of the sand table and smooth the sand. After several days and nights, the children observe that no footprints have appeared in the sand, and the water level has not changed. The children now conclude that Willie is not getting out of his cage at night.
"But wait." says Kahena, "Why should Willie get out of his cage? Willie can see that the watering can is covered." So the class decides to leave the cage in the middle of the sand table and take the cover off the watering can. The water level begins to drop again, yet there are no footprints in the sand. Now the children dismiss the original idea about the disappearance of the water, and Ms. W. takes the opportunity to give the class more experiences with the disappearance of water.
At Ms. W.'s suggestion, a container of water with a wide top is placed on the windowsill and the class measures and records changes in the water level each day using strips of paper to represent the height of the water. These strips are dated and pasted on a large sheet of paper to create a bar graph. After a few days, the students discern a pattern: The level of water fell steadily but did not decrease the same amount each day. After considerable discussion about the differences, Patrick observes that when his mother dries the family's clothes, she puts them in the dryer. Patrick notes that the clothes are heated inside the dryer and that when his mother does not set the dial on the dryer to heat, the clothes just spin around and do not dry as quickly. Patrick suggests that water might disappear faster when it is warmer.
Based on their experience using strips of paper to measure changes in the level of water and in identifying patterns of change, the students and Ms. W. plan an investigation to learn whether water disappears faster when it is warmer.
The children's experiences with the disappearance of water continue with an investigation about how the size (area) of the uncovered portion of the container influences how fast the water disappears and another where the children investigate whether using a fan to blow air over the surface of a container of water makes the water disappear faster.
From the National Science Education Standards (NSES Willie the Hamster pp 124-125)
a classic vignette
Suggested Labs and Activities
- The activities below match the only benchmark for this standard: 18.104.22.168.1 Identify where water collects on Earth, including atmosphere, ground, and surface water, and describe how water moves through the Earth system using the processes of evaporation, condensation and precipitation.
- The classic activity here is to have students directly experience evaporation, here are a few ideas:
- Benchmark 22.214.171.124.1Science Netlinks: Disappearing Water - Students will observe the amount of water in an open container over time, and they will observe the amount of water in a closed container over time. Students will compare and contrast the sets of observations over time.
- Benchmark 126.96.36.199.1 Science Netlinks: The Water Cycle: In this lesson, students build upon their previous investigations of water-and its different forms-by learning about the water cycle and its continuous flow around us. Students begin by reviewing what they already know about water and how it can freeze into ice or turn into a gas depending on how low or high temperatures become. They then learn about the water cycle and its key processes that affect our lands, oceans, and atmosphere. The ongoing need for fresh-water conservation is also highlighted.
- Benchmark 188.8.131.52.1 Where did the water go? FOSS Water Investigation 3- evaporation
- Part one- evaporation demonstration- two paper towels are soaked with equal amounts of water and then left to evaporate, one in a cup with a lid and the other in an open cup.
- Part two- students investigate the effects of air temperature and location on evaporation. they place cups with equal amounts of water in different locations around the school. they measure the temperature and amount of evaporation at each location. ** add in student predictions about where water will evaporate faster or slower and why- combine this with a reflection in their science notebook.
- Part three- surface area- same as above but using containers with different surface area, students will see that surface area of a specific volume of water affects rate of evaporation- again complete prediction reflection activity in science notebook.
- Part four- condensation, is an essential part of this investigation to teach the water cycle. students observe ice water and room temperature water. students see that condensation occurs when water vapor touches a cool surface and changes into a liquid. this is the introduction of the water cycle, students now know that water turns into vapor in the air and can turn back into water when the vapor touches a cool surface.
- Benchmark 184.108.40.206.1 Whole class activity from Willie the Hamster vignette above is a good demonstration, but students should have opportunities to complete this investigation individually or in small groups of 3 or fewer students, as describes above.
- Hands-on opportunity to "see" the water evaporate, students should have multiple opportunities to measure the water loss each day themselves, best practice would be to have each student measure the water loss from their own container, rather then a whole class example where the teacher demonstrates, as in the willie the hamster vignette from above.
- For students to truly understand where the water is going, they may need to repeat an evaporation activity more then once, using different containers and placing the water in different locations around the school.
- Water cycle- The sequence of condensation and evaporation of water on Earth, causing clouds and rain and other forms of precipitation.
- Evaporation- The process by which liquid water changes into water vapor
- Condensation- The process by which water vapor changes into liquid water, usually on a surface
- Watershed- the land that water ﬂows across or under on its way to a stream, river, or lake.
- Cycle: A process or action that repeats itself in the same order over time.
- Circulation- The flow or motion of water in or through a given area, as in hte water cycle
- Atmosphere- The atmosphere is a layer of gases which surrounds the entire Earth.
- Precipitation- is any form of liquid or solid water particles that fall from the atmosphere and reach the surface of the Earth.
- Groundwater- is water that is found underground in cracks and spaces in soil, sand and rocks
- Surface water- is water that collects on the ground or in a stream, river, lake, wetland, or ocean
- Water vapor: The gaseous state of water
- FOSS Web Evaporation activity:
- Blogging: student blogging about scientific investigations can be a successful way to strengthen understanding, when student collaborate on ideas and participate in discourse understanding of a concept becomes clear. through blogging an observant teacher can quickly see student misconceptions and ask questions to get student learning back on track.
- NOAA Water cycle game
- Use a graphic organizer like inspiration (software) or web-spiration (free web program) for pre/post teaching of students: students can make connections to water in their community- were do we find water? (this can also be done pen and paper) What do we already know about water:
- Social studies and language arts connection- research water storage and delivery systems for your community. Visit a local water reclamation and treatment plant.
- Math- when doing part 3 surface area- correlate this with teaching area in math, this is a great opportunity for teachers to demonstrate an authentic use of measuring area. using graph paper under the object that will hold the water will allow students an easy way to measure how many square centimeters of surface area an object has. Have students make a graph of surface area in square centimeters to amount of water that evaporates.
- Exceptional resource- includes complete explanations of student misconceptions. Beyond Penguins and Polar Bears web site
- USGS water science for schools website on the Water Cycle or follow a drop
- Franklin Institute's Water in the City website can help to broaden students' understanding of water and the continuous, global water cycle. This resource covers the "Water Basics" and science of water and also presents an analysis of Philadelphia's water system and case studies on waterways throughout the world.
- From USGS (FREE)great for kids :
From USGS (more complicated version):
Assessment of Students
Wet Jeans (Keeley, P., Eberle F., Farrin L.,(2005) Uncovering Student Ideas in Science Volume 1., Arlington, VA, NSTA Press. p. 155)
Living things need to use a lot of water, so why isn't the earth's water supply used up? (Teaching Science for all Children, Page 391)
Six assessment questions here- (Multiple choice, T/F, Short answer, constructed responses, etc)
1. (Level 3 ) Constructed Response: Water appears on the outside of your glass of ice water. In your own words, explain what's happening?
2. (Level 1) Clouds are formed by:
A. Cool air rising
B. Water vapor condensing
3. (Level 1) Moisture that falls to the ground is called:
4.-8. (Level 1) Label the picture below. See this site.
1. The Sun
5. The Ocean
5. Where does water in a lake get most of its energy to evaporate (level 1 recall)?
1. The sun heating the lake
2. Green plants living in the lake
3. Streams entering the lake
4. Cold springs under the lake
Assessment of Teachers
- Wet Jeans (Keeley, P., Eberle F., Farrin L.,(2005) Uncovering Student Ideas in Science Volume 1., Arlington, VA, NSTA Press. p. 155) An excellent teacher assessment.
- Teachers reflection prior to teaching this unit: What do I already know about the processes involved in the water cycle? What do I need to know about the processes involved in the water cycle?
Struggling and At-Risk
Bricks and mortar vocabulary labels and word walls, vocabulary posters, pre-teaching: accessing prior knowledge, graphic organizers, each activity needs to have reading, writing, speaking, listening component.
Bricks and mortar vocabulary labels and word walls, vocabulary posters, pre-teaching: accessing prior knowledge, graphic organizers, each activity needs to have reading, writing, speaking, listening component. (Keenan). On the kids health website the content can be read by a computer generated voice
1. Concepts should be directly linked to students' background experience. This experience can be personal, cultural or academic.
2. Links should be explicitly made between past learning and new concepts.
3. Key vocabulary is emphasized. New vocabulary is presented in context. The number of vocabulary items is limited.
4. Consistent use of scaffolding techniques throughout the lesson. Introduce a new concept using a lot of scaffolding and decrease support as time goes on. Restate a student's response or use think-alouds
5. Use of a variety of question types, including those that promote higher level thinking skills.
Allow students to follow an aspect of water cycle research they are passionate about, complete an independent or small group research project (teachers provide scaffold for student research) about water resources on earth and water quality.
Choose a country other then the USA, as a class learn about water quality issues of this country (use, books, video, Internet)- is the water safe to drink? how is water treatment similar or different in this country? have students complete a Venn diagram about similarities and differences in water quality issues between the two countries.
Bricks and mortar vocabulary labels (bricks are content specific vocabulary like evaporation. Mortar are words that a student might need but are not content- for this unit examples might be- system or cycle) and word walls, vocabulary posters, pre-teaching: accessing prior knowledge, graphic organizers, each activity needs to have reading, writing, speaking, listening component. (Keenan)
Focus on evaporation, condensation- not the parts of the water cycle. Look for hands-on experience with evaporation and condensation- just reading about it is not enough. Carefully evaluate a teachers use of a typical water cycle poster- are they reinforcing the misconception that water travels immediately up to the clouds, but that it actually exists around us as an invisible gas. Humid weather is an example of water in the air that a teacher could use to help fourth grade students better understand evaporation.
Have students conduct simple evaporation investigations at home, advanced connection, have students and parents examine the connection between humidity and evaporation.