grade 7: how much water do you use?
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How Much Water Do You Use?
Description: This lesson is designed to accompany the Grade 7 GUSH Workshop. Students will gather information on their personal water consumption and learn how to present and interpret this data through the use of relative frequency tables and circle graphs.
Grade Level: Grade 7 Setting: Classroom
Learning Objectives: 1. Calculate personal water consumption and collect similar data from other classmates. 2. Organize water consumption data and present in the format of a relative frequency table and a circle graph. 3. Interpret classroom water consumption data and think of ways to reduce personal consumption.
Duration: 90 minutes Key Words: -‐Consumption -‐Range -‐Frequency -‐Relative Frequency Table -‐Circle Graph
Related Curriculum Links: Natural Resources – describe a variety of ways in which people use and manage renewable, non-‐renewable, and flow resources to meet their needs; – communicate the results of inquiries for specific purposes and audiences using computer slide shows, videos, websites, oral presentations, written notes and descriptions, drawings, tables, charts, diagrams, maps, models, and graphs Data Management and Probability – collect data by conducting a survey or an experiment to do with themselves, their environment, issues in their school or community, or content from another subject, and record observations or measurements; – collect and organize categorical, discrete, or continuous primary data and secondary data (e.g., electronic data from websites such as E-‐Stat or Census At Schools) and display the data in charts, tables, and graphs (including relative frequency tables and circle graphs) that have appropriate titles, labels (e.g., appropriate units marked on the axes), and scales (e.g., with appropriate increments) that suit the range and distribution of the data, using a variety of tools (e.g., graph paper, spreadsheets, dynamic statistical software); – read, interpret, and draw conclusions from primary data (e.g., survey results, measurements, observations) and from secondary data (e.g., temperature data or community data in the newspaper, data from the Internet about populations) presented in charts, tables, and graphs (including relative frequency tables and circle graphs); Equipment: -‐ Pencils -‐ Rulers -‐ Calculators
Consumables: -‐ Copies of Tin Roof Global‘s Water Consumption Calculation Sheet (attached) -‐ Blank paper
-‐ Protractors -‐ Compasses
-‐ Lined paper
Safety Considerations: N/A Lesson: Starter (5 minutes) Ask students to think of all of the ways that they use water in a day. Write their suggestions on the board. Activity (80 minutes) Hand out the Global Water Consumption Calculation Sheets. Tell students to first figure out how much time they spend completing each of the activities listed in one day. Once they have completed that, tell them to calculate the litres of water used for each activity and then add up the sum for each activity to get a total amount of litres used. Instruct students to write their total daily water consumption up on the board. Explain that they are going to represent this data in two different forms, as a relative frequency table and as a circle graph. Ask the class what the range in results was. When they have determined the range, explain that they need to break up this range into sections, and to be as accurate as possible they should try and have between 5-‐10 sections. Ask the class what an appropriate section size would be (ie: if the range was 100 – 300, should the sections increase by 25’s, 50’s, 100’s? If they pick by 25’s, then there will be 8 sections with the first one ranging from 100-‐124, the second one ranging from 125-‐149 etc.) Explain to students that a relative frequency table shows how popular a certain type of data is. Draw a relative frequency table on the board and label the first column “Litres of Water Used”, the second column “Frequency” and the third column “ Relative Frequency”. Ask the students to copy a version of their own on lined paper (using a pencil and a ruler). Add in the section values (ie: 100-‐124, 125-‐149 etc.) under the first column and ask students to do the same. Now explain to students how to fill in the remainder of the table. Ask the class how many results up on the board fit into the first section (ie: range between 100-‐124) and then add that value into the second column of your table. Ask students to try and complete the rest of this column on their own. After 5 minutes, take-‐up students’ answers on the board or have them come write in the values themselves. Finally, explain that to fill in the third column they must divide the number in the second column by the total number of students in the class (ie: if the class has 30 students, and there were 4 results that fit into the first range, divide 4/30 = 0.13). Ask students to try and complete the rest of this column on their own. After 5 minutes, take-‐up students’ answers on the board or have them come write in the values themselves. Explain to students that circle graphs (pie charts) are graphs that use “pie slices” to show relative pieces of data. Ask students what it is called if they were to jump and spin one full rotation (360). Tell students that a full circle has 360 degrees. Explain that by multiplying the relative frequency of each result by 360, they can figure out the size of each “pie slice” (ie: 0.13 x 360 = 48, so their first piece of data will take up 48 degrees, or 48% of their circle graph). Tell students to complete this calculation for the remainder of
their values in the third column. When they are finished, all of their answers should add up to 360. Tell students to draw a circle on blank paper using a pencil and a compass. Next, instruct them to use their protractor to draw their first section of the circle graph (you may want to demonstrate this on the board). Instruct them to draw the remaining sections of their circle graph until it is complete. They can then colour-‐code each section and provide a key to signify what each colour represents. When students have finished, ask them to interpret their circle graphs. How much water do most people use in a day? Are there more students at the higher end of the range or the lower end? Conclusion (5 minutes) As an exit card, have students think of three different ways they can reduce their water consumption in a day (ie: turning off tap while brushing teeth, using bucket to collect shower water while they wait for it to warm up etc.) Accommodations/Modifications This lesson could be split into two, with the first lesson focussing on relative frequency tables and the second lesson on circle graphs. Use the students themselves as a visual guide when making the relative frequency table/circle graph. Place the number ranges along the sidewall of the classroom and have students stand by their number range. Students can then visualize the distribution of data. Provide students with computers to create their circle graphs on excel or other graphing platforms before drawing their own. Extensions Have students give the water consumption survey to other grade levels to compare water consumption data for students of different ages. They can then use this extra information to build a second circle graph (ie: grade 8 water consumption vs. grade 7 water consumption).
Water Consumption Calculation Sheet
Let’s see how much water you use in one day! Decide how many times you complete each of the activities listed in the table below and multiply these with the amount of water used by each activity. For example, if you shower for 10 minutes/day, you use (10 x 9.46) 94.6 litres of water while showering. Finally, add up the amount of water used for each activity to get a total for the day.
Activity Amount of water used
Number of times activity is
completed per day
Calculated amount of water used per day
Shower 9.46 litres per minute
Bath 264.98 litres
Toilet 13.25 litres per flush
Front-‐Loading Washing machine
75.70 litres per load
Top-‐Loading Washing machine
151.42 litres per load
Dishwasher 22.71 litres per load
Hand wash dishes 75.70 litres
Tap 3.78 litres per minute
Total Amount of Water Used Per Day: