Evaporation. Where did the water go? Overview. Grade Level: K and 2

Transcription

1 Where did the water go? Grade Level: K and 2 Time: Grade K One day to set up, three days to observe, and one final day to process Grade 2 Two days to set- up, four days for data collection, and two days to process with a possible extra day for presentations By: Mary Jo Bohener (Amherst County Public Schools Grade K) Scott Strang (Amherst County Public Schools Grade 2) Overview Students will work in groups designing their own investigations to answer teacher- posed questions about evaporation. Students will make connections to previously learned information as they design an apparatus to test their predictions for grade K. Grade 2 students will take it a step further by investigating factors that play a role in evaporation including temperature, size of container, and number of holes in a container s lid. They will use measurement tools, record data and observations, and present what they have learned to their classmates. This lesson was developed through the Introduction to Inquiry: A Professional Development Model to Reform Teacher Practices project directed by Science by Inquiry at Sweet Briar College and funded by the Virginia Department of Education Math Science Partnership Grant (MSP) Page 1

2 Context It is challenging to make the study of matter concrete for young students. There are many concepts that run counter to intuition: an empty jar is not empty but rather full of air that has mass that can be measured; the mass of an object has more to do with how closely packed its imperceptibly small atoms are than its size; water can be rendered invisible by turning it into a gas; any kind of matter can exist as a solid, liquid or gas depending on the amount of heat energy it has. All this can be mind- boggling to students even though they ve had some direct experience with many of these concepts. Kindergarten students learn that objects can be described using physical properties and that water occurs in different phases. These ideas are the building blocks for understanding matter. This lesson is embedded in a unit focused on the phases of matter with water as a basis. Amherst County second graders study matter during the second nine weeks; specifically different properties of solids, liquids and gases; how to measure solids and liquids; and how water changes its phase of matter as heat energy is added or removed. Students also continue to develop their science inquiry process skills with emphasis on identifying conditions that influence a change and making multiple trials to ensure accuracy. This investigation of evaporation naturally follows from the mulch inquiry in the garden and the study of weather phenomena from the first 9 weeks. (For more information on this, see the lesson Waterwise Gardening which is published with this set of teacher resource materials.) After investigating factors that affect evaporation in this lesson, students will create a model of the water cycle in an empty aquarium and investigate the relationship between humidity and the temperature at which condensation occurs. Finally students will create a classification scheme for solids, liquids and gases based on their observations of the phases of matter in various experiments. Overall, the students did deepen their understanding of evaporation. I think it will make it easier for them to tackle the tough concept of condensation, having this investigation to look back on. ~Scott Strang Page 2

3 Objectives Know o Vocabulary: evaporation, melting, solid, liquid, water vapor, gas. o Vocabulary: millimeter, milliliter, gram, mass. (Grade 2) o Heat causes ice to melt and increases evaporation. o The movement of air increases evaporation. (Grade 2) o Appropriate tools for measuring temperature, volume, length, and mass. (Grade 2) Understand Do o When water evaporates it doesn t vanish, it changes its phase from liquid water into a gas, water vapor, which is invisible. This is the basis for the understanding that all matter has mass and volume. o When investigating a question, a fair test must be devised in which only one variable can be manipulated. o Multiple trials ensure greater accuracy in a scientist s data. (Grade 2) o Develop a plan of investigation in order to answer the inquiry question. o Use appropriate tools to measure volume or depth (or both) and mass of a liquid in a container. (Grade 2) o Maintain consistency in collecting and recording data to ensure a fair test. (Grade 2) o Present the data in a graph. (Grade 2) o Analyze and interpret data to answer the inquiry question. o Present the results orally to the class. Page 3

4 Standards Virginia Standards Science K.1 The student will demonstrate an understanding of scientific reasoning, logic, and the nature of science by planning and conducting investigations in which a) basic characteristics or properties of objects are identified by direct observation; h) observations are recorded; k) objects are described both pictorially and verbally. Science K.5 The student will investigate and understand that water flows and has properties that can be observed and tested. Key concepts include a) water occurs in different phases; Science K.10 The student will investigate and understand that change occurs over time and rates may be fast or slow. Key concepts include b) changes can be observed and measured. Science 2.1 The student will demonstrate an understanding of a) observations and predictions are made and questions are formed; c) observations are repeated to ensure accuracy; e) length, volume, mass and temperature are measured in metric units and standard English units using the proper tools; g) conditions that influence a change are identified and inferences are made; h) data are collected and recorded, and bar graphs are constructed using numbered axes; j) conclusions are drawn; and k) observations and data are communicated. Science 2.6 The student will investigate and understand basic properties of solids, liquids, and gases. Key concepts include a) identification of distinguishing characteristics of solids, liquids, and gases; b) measurement of the mass and volume of solids and liquids; and c) changes in phases of matter with the addition or removal of energy. Page 4

5 Preparation What You Need Grade K Lesson Have multiples of the following items available for the students to choose as they are designing: Ice cubes made with food coloring added (to aid in visual) Clear plastic cups Clear plastic sandwich sized bags Clear plastic cling wrap Rubber bands Sharpie markers Tape Grade 2 Lesson Have multiples of the following items available for the students to choose as they are planning: Graduated cylinders Rulers Thermometers 4 oz. cups with lids Variety of cups in different shapes Heating pad Cookie tray Tape and permanent markers for labels Balance scale and gram weights Page 5

6 Getting Ready Grade K Lesson Several days before the activity Ask the students to draw the three phases of water as a pre- assessment. Use the results as a starting point for talking about the forms of matter. Student will need to know some properties of the phases of matter before embarking on this lesson. Before the day of the activity Prepare the ice cubes by freezing Set out the materials Be sure to have an area where the cups can be accessible, but not disturbed for a few days Grade 2 Lesson Before the day of the activity Set out the materials Be sure to have an area where the cups can be accessible, but not disturbed for a few days Page 6

7 Grade K Session One: Planning the Investigation Introduce the Investigation 1. Review what students already know about the three phases of water. This may be teacher- directed or with a KWL chart. 2. As the students How can we produce the three phases of water starting with ice cubes? 3. Show the students the ice cubes and the other materials that they have access to. 4. Put students in groups of four 5. Have the groups come up with a plan to show the three phases of water. After the group plan has been approved by the teacher, allow them to get the materials they will need. Ask the students, as they plan, to think about what will happen to the ice. It was interesting to listen and watch the ideas that were being generated by the groups of students. They would put the ice cubes in a plastic cup and then put cling wrap and a rubber band around the cup. One table decided to put the ice and cup inside a ziplock baggie. One table put the cling wrap over the ice and the cup with a rubber band and also put it inside a ziplock baggie. ~Mary Jo Bohener 6. Allow students to set their design with ice cubes aside, but allow them to check on their designs at least by the end of the day to see if there is any change in the ice. 7. After the students have their investigation set up, you may choose to demonstrate the three phases of water using a closed electric skillet and ice. The students can observe the ice melt and turn into water and can see the water vapors collecting on top of the skillet. Also during the inquiry I asked questions to guide thinking by the students. What do we need to make ice melt? During the video on Friday what caused the water to evaporate? What do we want to find on our baggies or clingwrap. ~Mary Jo Bohener Page 7

8 Over the Next Two to Three Days Set aside a few minutes each day for students to observe the ice in their designs and to record their observations in their journals using drawings. Many of the students went right over to the window in the morning to inquiry about what had happened with their cups of melted ice(water). A couple of students said, We have a liquid now. Students that didn t go over on their own were brought over by one of the intrigued students. It made for quite a bit of excitement first thing in the morning. As the day progressed we kept checking for evidence of water vapors on the baggies and or cling wrap. By the afternoon the students could see the water collecting on the baggie or cling wrap. They were very excited with their success. ~Mary Jo Bohener Consider allowing students to disassemble their design to allow the water as a gas to escape the closed apparatus. This will allow students to watch the water, over time, to evaporate completely. The students wanted to extend the inquiry by removing the cups from their covers to see the liquid evaporate. The questioned posed was, will the liquid evaporate completely. We added some math by measuring the liquid when we removed the covers and we will measure it again during the week. ~Mary Jo Bohener Page 8

9 Grade K Session Two: Make Conclusions Based Upon Data Gather students and ask them to share what happened to the ice that was in their design. Allow individual students to share using their pictures as evidence. Have students take a post- assessment where they draw the three phases of water. For a post assessment for this unit the students were asked to draw the three stages of water. All students were able to draw all three phases of water. Some of the pictures that were drawn showed that the students understood the key concept.(examples: solid: ice cubes, icicles, freezing rain, and ice on a pond, liquid: lake, pond, water in a cup, water dripping from a faucet, and a pitcher of water, gas: cup with hot chocolate and the steam, kettle pouring hot water and the steam, and hot soup with steam) ~Mary Jo Bohener Page 9

10 Grade 2 Session One: Planning the Investigation Note, this lesson was taught after Waterwise Gardening by Scott Strang. The link to the previous inquiry lesson creates a powerful overarching theme to the school year on gardening and factors that affect plants grown outside. If you do not have a garden, then you may begin the lesson with a KWL on evaporation or make another connection appropriate to your students. 1. Discuss the plants in the garden and the problem of keeping them watered. Ask: If we had a better understanding of what causes evaporation, wouldn t we be better equipped to maintain the right amount of moisture in the soil for the plants? 2. Begin a whole class KWL on evaporation. 3. Present the questions for investigation under the W part of the KWL: How does temperature affect evaporation? How does the shape of the container affect the rate of evaporation? How do holes in the lid of a container affect the rate of evaporation? 4. Have students individually choose a question to investigate. Have each student list in his/her journal what kinds of materials he/she will need to answer the question. Then have each student draw a diagram of what his/her experiment will look like once it is set up. 5. Collect students journals and use this information to group students for the following day. I gave them the three questions to choose from and asked them to pick one. Then they individually wrote a First, next, then, last narrative with illustrations of how they would investigate that question. Since I gave them the questions to investigate, but largely left it up to them to plan how to conduct the experiment and collect and graph their data, this [type of instruction] qualifies as a guided inquiry. ~Scott Strang Page 10

11 Grade 2 Session Two: The Investigation 1. Have all of the students who selected the same investigation question in their journal gather in a group. Within each of the three groups (one group per question), ask the students to compare their individual lists of tools needed to conduct the investigation and the drawing of their setup. Investigation Questions: How does temperature affect evaporation? How does the shape of the container affect the rate of evaporation? How do holes in the lid of a container affect the rate of evaporation? 2. Have each student write a plan for their investigation on a 4- frame storyboard (draw a picture and write a caption for what will be done First, Next, Then and Last ). Then, put students into small groups of 2-3 students (with the same question) who will meet to come up with one collaborative plan for investigating their question. 3. Meet with the pairs and/or groups as they are planning and monitor their progress. Provide support so that their struggles will be productive. Discuss what kind of data will be collected, how it will be collected and how it will be recorded. We discussed how they would know if evaporation had occurred. I had introduced matter as a vocabulary word for a story about baking a cake that we d read the week prior in reading class. We d discussed the different definitions of matter. One student knew that matter took up space. All of the groups had come up with this as the thing they would be measuring. I introduced the other defining characteristic of matter, that it has mass, and I asked if this could also be measured to see if the water was evaporating. I taught them how to use a balance scale. I then asked the groups to discuss how they would collect their data, and had them set up their experiments. Almost all of the groups decided that they wanted to measure both mass and volume. Only one pair was able to work efficiently enough to get their experiment set up and data collected that day. The rest finished the following day. ~Scott Strang 4. Ask pairs/groups to come up with a draft of a sheet on which they will collect data. Have all the pairs who are answering each question get together in a group to decide what the best format for their data collection sheet will be. 5. Once each plan is ready, have the students set up their experiments. HINT: Restrict the number of cups to 3 or 4 maximum. The individuals each want to have their own cup on the heating pad, and their own cup on the windowsill and the desk. This makes for too many cups to measure, too many opportunities for spilling, and undermines the collaborative nature of doing science. Teamwork is IMPORTANT. Page 11

12 Over the next Four Days Set aside 15 minutes each day for students to conduct data collection and for them to record data and observations in their journals. Collect data for at least 4 days. Extending the investigation over the weekend might produce dramatic results, but would complicate graphing the data as 2 days of values would be missing, and there is the possibility of a cup s water evaporating completely. The students wouldn t know on which day the water was all gone. Page 12

13 Grade 2 Sessions Three and Four: Data Analysis and Presentations Data Analysis Once all data is collected, pairs will interpret and graph their data and present their findings to the class. Presentations to the Class Challenge the groups to determine which factor had the greater effect on evaporation (temperature or exposure to air). Complete the class KWL. Each student will finally complete the post- lesson assessment quiz, and fill out a summary page of what he/she has learned from the inquiry. The groups that were investigating the question about different shapes of containers started out by filling the cylinders, beaker and cup to the same height, instead of putting the same volume of water in each. We discussed whether the vessels had different amounts of water and if it would matter. They decided that it would be easier to collect data and graph it if they started with the same volume. For the next 3 class days students measured the volume and mass of their cups of water and recorded their data in their notebooks with varying degrees of organization and quality control. ~Scott Strang Page 13

14 Grade 2 Embedded Math Connections On the last day of data collection, remembering the struggles some of them had had graphing their mulch investigation data, I had them do a math activity that required them to transfer data from a table to a graph, and then use the table and graph to estimate the value of some missing data. When the groups had finished collecting their data on volume and mass, I asked them to work with their partners to determine how the axes of their graphs would be labeled. All of the groups decided to label the x- axis with the days that data was collected, and the y- axis with the volume (or mass) values. The groups that measured both volume and mass wanted to put both on the same graph. I explained that it would be much easier to make 2 graphs. Then I asked them to figure out how many rows and columns they d need, before heading to the computer lab to create the graphs as a table in a word document. Working this out generated a lot of math connections on different levels. Almost all of them had values that were too high to graph on a single sheet of paper, so in order to accommodate the data, each row on their graphs would have to count for 2. I had them round their highest value up to the next ten, find half of that, then add one row for labeling the columns. With some students, as they determined how many columns they d need, we made a connection to a multiplication idea that had come up in another context (days of data x # of cups). I was surprised at how readily and successfully the students took on these math challenges. ~ Scott Strang Page 14

15 Assessment Objectives The overall learning objective of this lesson (The Big Idea) is for students to understand that water can occur in different phases, including a gas, and to understand the factors that can affect evaporation. These ideas are the foundation of understanding matter in later grades. Learning goals also include: designing an apparatus that can show the phases of water (Grade K); making systematic observations; graphing and analyzing data to answer an investigation question (Grade 2); and practice with scientific processes through investigation (trials, variables, etc.) that lead to a deeper understanding of the nature of science. Pre- lesson Assessment Grade K: Have students draw the three phases of water. Use this information to determine the level of instruction that needs to be done before students can design their own apparatus and to compare with a similar post- lesson assessment. Grade 2: To assess students ability organize data in a chart or table, ask students a question like what kinds of data would Jesse need to collect to investigate hummingbird nectar color preferences? Design a data collection sheet she might use to conduct her investigation. Use a whole class KWL on evaporation to assess students prior knowledge. Use this information to determine what misconceptions may need to be addressed during the lesson. Assessment Plan The students will record their observations in their science journals daily. Students data collection sheets will be used to demonstrate their ability to organize the information and to make consistent and accurate measurements. (Grade 2) Listening in on their group discussions will help assess engagement and the degree to which their thinking extends beyond the most concrete (active) level. The post- assessment will demonstrate whether or not their understanding of evaporation has deepened and if their inquiry skills have developed. Have students complete the Learn part of the KWL on their own along with any other wonderings. Application: Explore and explain how plants in the desert conserve water, and how it relates to their investigation. (Grade 2) Formative Assessments The student s science notebooks will contain their data collection sheets, which will reflect their ability to use the tools to measure length, volume and temperature. It will also demonstrate their ability to record data and make observations. Assess student s abilities to chart and record data as they are working. If it seems necessary, intervene Page 15

16 and do a mini- lesson on how to make a chart to record data. Use some good students charts as a model and then ask student groups to decide how many rows and columns they need for each day of data collection. Allow students to go to the computer lab to create a table in a word document. Ask students to enter the data they already have. Listening in on their group discussions will help assess engagement and the degree to which their thinking extends beyond the most concrete level. It will also allow me to monitor their collaboration skills. Monitor students as they are making measurements. Check each individual at least once to ensure that they are taking accurate measurements and intervene if necessary. While I was dismayed at the general shoddiness of data collection during their investigation, when I met with the groups as they did their graphing they were able to identify numbers in their data that were unexpected. They attributed these to a spill incident where someone had refilled the cup without reckoning how much had been in it before the spill. ~Scott Strang Summative Assessments: Grade K: Have students draw the three phases of water and compare to the pre- assessment to determine what the students learned from the lesson. Grade 2 The post- assessment will demonstrate their understanding of the vocabulary, and specific content as well as their understanding of what it means to do a fair test. They will produce a diagram of where water from a rainstorm goes after it lands on the garden to demonstrate their level of understanding of the water cycle. Students will also explain how plants in the desert conserve water, and how it relates to their investigation. Finally, I had them write responses to a set of questions to assess their grasp of important science ideas: Did they appreciate the relationship between the data and observations we collected and the question we were trying to answer? How did they interpret their data to help them answer the question? How well did the numerical data match their observations? What did they do to try to make it a fair test, and what issues complicated that effort? What further questions did they have and how might they test them? What kinds of things make more/less evaporation happen? Did your data help you answer the question? Explain why it did or didn t. Page 16

17 Acknowledgements VA Science SOL Curriculum Framework Inquire Within by Douglas Llewellyn Weaving Science Inquiry and Continuous Assessment Carlson, Humphrey, Reinhardt; Corwin Press 2003 Page 17

18 Appendices: Handouts 1. Student response sheet for 2 nd grade evaporation investigation after they have completed their presentation 2. Pre and post- assesssment for 2 nd grade evaporation investigation Page 18

19 Appendix 1: Student response sheet for 2 nd grade evaporation investigation after they have done their class presentations Name: Which cup evaporated the most? Which cup evaporated the least? What is the answer to your question? How did you use your data to help you answer your question? What would you do differently if you had to do this experiment again? What kinds of things have the greatest effect on evaporation? What kinds of things have the least effect on evaporation? How do you know? Page 19

20 Appendix 2: Pre and post- assesssment for 2 nd grade evaporation investigation Name: 1. Jim Bob is crawling through the desert on the hottest summer day of the year. He finds a large cup of water. He drinks some of it, but he want to save some for later. What should he do to keep it from evaporating, so he can drink it later? 2. There is a puddle of water on the sidewalk. Circle the kind of weather you think will make it evaporate fastest, and explain your answer: A hot, humid cloudy day, or a cool sunny day, or a hot windy night. Jesse wants to know what color of sugar water her hummingbirds prefer. Help her plan her investigation: What measuring tools will she need? What else will she need to do her experiment? What will she be measuring? What should she do First Next Then Last Page 20