DRAFT 1 Lesson Title: A Little Exercise Goes a Long Way Grade Level: High School Grade 9 Subject Area: Math Beginning Algebra Setting: Classroom, Gym, Track and School Garden area (outside) Instructional Time: One to two class periods (55 to 90 minutes) High School Expectations: Strand 2 Algebra and Functions A1.2.1 Write equations and inequalities with one or two variables to represent mathematical or applied situations, and solve them. A2.4.1 Identify the family of function best suited for modeling a given real world situation. A3.1.1 Write the symbolic forms of linear functions (standard, point slope and slope intercept) given appropriate information and convert between forms. A3.1.2 Graph lines given appropriate information. MNN Outcomes: Be physically active every day as part of a healthy lifestyle. Balance caloric intake from food and beverages with calories expended. Goal: The purpose of this lesson is to encourage students to experience and use mathematics in order to make informed decisions regarding physical activity and calories and health. Objectives: Collect data as part of a scientific investigation and change variables to see how factors control the response. Explain the relationship between physical activity and calorie expenditure. Background: It is well understood that health is related to regular activity with some occasional vigorous activity. Simply walking more or doing more work outside or getting outdoors in a park can improve overall health by reducing weight and improving cardio and respiratory function. This is not a linear relationship. As a person s heart rate increases the amount of calories expended per hour increases in a power relationship. For example, sitting watching TV burns about 75 calories per hour with a heart rate of about 80 beats per minute (bpm). A brisk walk will boost your heart to about 120 bpm but calories will increase to 300 calories per hour,
and climbing stairs will increase your heart to about 150 bpm but you burn about 700 to 900 calories per hour depending on how fast one climbs. The USDA and NIH recommend, in order to stay healthy, that a person should be active at least five days per week for at least 30 minutes each day. For example, a half hour walk or gardening or playing soccer with you kids. Activities like these will burn about 200 calories and improve metabolism over time which will allow more calories to be burned while resting. Gardening has many health benefits. The work required to maintain a garden requires physical activity. On average, garden work burns 4 calories per minute (240 calories per hour). MyPyramid recommends increased consumption of fruits, vegetables and whole grains all of which can be produced for little expense in a garden. The result of garden work is more flavorful food, ample fresh vegetables in the summer and fall and the opportunity to save even more food dollars by canning or preserving the harvest for consumption during the dormant season. Vocabulary Terms Correlation a linear mathematical relationship between two quantitative variables that indicates how strong the association between them is. Association the general relationship between two variables Advance Prep Teacher needs to make a black line master copy of the data collection chart or make their own. Need to discuss using the facilities with respective physical plant administrators at school such as athletic director or staff responsible for garden. Need time to collect and organize garden tools. Supplies MyPyramid poster, http://teamnutrition.usda.gov/educators.html (Teacher note: MyPyramid for Kids is for children 6-11 years. If the majority of your class is over 11years of age use the adult MyPyramid.) Stopwatches or watch (student) with second hand (one per pair) Space for walking/running ¼ mile distances Clipboards (one per pair) Garden tools (rakes, shovels, hoes); maybe 2 of each Heart rate monitors, if your school has some (If not, be prepared to instruct students in taking a pulse) Copies of data collection table Skin protection (SPF 15 or higher) Drinking water Safety Notes: Students with propensity to sunburn may need sunscreen; if doing vigorous activity then bring water. Watch the shovels!! It may be a good
idea to have an extra adult or two so students can spread out over the facility, and the teacher does not need to monitor all the stations. Procedure: Review MyPyramid with the students. Review the intake recommendations per food group and recommended daily amount of physical activity. How closely do the students think they follow these guidelines? Why do they think these guidelines exist? Why are they important? What small changes can they make in order to more closely follow the guidelines? Explain to students that virtually all physical activity is beneficial. Can they think of non-traditional (non-sport types) of physical activity? Answers may include house work, gardening, and more. Ask the students how many of them have a vegetable garden at home? Do they have chores? What do they think some of the differences are in the food grown in their garden in comparison to the food from the store? Share the amount of calories that people burn doing garden work on average (4 calories/minute or 240 calories/hour). What other benefits to gardening can the students think of? (Inexpensive fresh food, more flavorful food, fresher food and thus more nutritious food). Explain that the class will collect data as part of a scientific investigation and change variables to see how factors control the response. They will explore the relationship between physical activity and calorie expenditure. During this activity they need to pay special attention to the activities they may do in a garden. Take the students outside and have them spread out to various stations and use the data collection sheet to measure their heart rate after dong two minutes of the activity. Do a practice round of measuring heart rate to facilitate proper data collection. Have the students record heart rate for each station on the data collection form. Have them do this three times. If each student does not get to all the stations, it is OK, since the classroom data can be photocopied for analysis. Teacher can add more or less stations depending on facilities and time. Each student should fill in the data sheet from other student s data if there is not enough time to complete each activity.
Students should answer the questions using their own data sheet. Discussion can occur about the variability of the data from one student s statistics to another.
Note: Calories burned per hour was calculated using the calculator on Caloriesburned.com Column 1 Column 2 Column 3 Column 4 Column 5 Activity Type Sitting in Class Walking Leisurely Heartbeats after 6 sec Column 2 X 10 Heart Rate (bpm) Calories Burned Per Hour (130 lbs) Calories Burned Per Hour (180 lbs) 104 122 147 204 Walking Briskly 295 408 Jogging (3 min per lap) 413 532 Running (2 min per lap) 737 1021 Raking (moving leaves) 254 351 Shoveling (move soil into a wheelbarrow) 531 735 Cultivating Dribbling/Shooting Walking Stairs 295 408 265 367 472 635
Student Pages Questions Once you have finished, find other students that have heart rate data that you might not have been able to complete and fill in you data collection form from their data. 1. Make a scatter plot of the data with heart rate on the X axis and calories burned on the Y axis. Label and scale your graph. Draw a best fit line. 2. Is there a linear association between the two variables, or is it more curved? If it is linear, then make an equation using the point slope formula. Describe the association and the meaning of the slope, in context.
3. If your heart rate is 120 bpm, then estimate how many calories you might burn. Which activity or activities are in this range? 4. Gardening and farming activities vary in strenuousness. What activity was the most strenuous? Can you think of some other yard work activities that might be similar to the ones you measured? See if you can come up with at least three. 5. Burning fat is best done when your heart rate is between 60% and 70% of your maximum hear rate, according to the 24/5 Complete Personal Training Manual, 2000. For example, if you are 14, your typical maximum is heart rate about 200 bpm. Sixty percent of this is 120 bpm. The typical teen will burn about 300 calories in an hour at this rate, and about 150 of these calories are fat. A pound of fat is about 3500 calories. If you burn an extra 150 fat calories each day, how long will it take to lose a pound of fat? 6. If the average teen spends just one hour per day of moderate activity like shooting baskets, playing soccer or Frisbee, walking or yard work instead of watching TV or playing video games, then he or she could lose how much fat weight in one year? 7. Extension: If you have a sedentary lifestyle, then make a pledge to yourself to increase your activity just a few days each week. Try to increase this to five days per week. Talk with your parents or a teacher or other adult in your life you think would help you with this. Keep track of what you are doing and journal about the experience. One of the best activities you can do is help out in the school garden. Talk to the garden supervisor on how you can help.
References Robert Larson Duyff, Complete Food and Nutrition Guide, 2 nd Edition, 2002, American Dietetic Association, John Wiley & Sons, Inc., Hoboken, New Jersey. Kock, Pamela,,et. al., Choice, Control & Change, Draft Lesson Plans, Teachers College Columbia University, September 2007. Kock, Pamela,,et. al., Growing Food, Teachers College Columbia University, 2007 Ways to Enhance Children s Activity and Nutrition http://www.nhlbi.nih.gov/health/public/heart/obesity/wecan/index.htm Dietary guidelines for Americans 2005 from the US Dept of Health ad Human Services, USDA http://www.health.gov/dietaryguidelines/dga2005/document/pdf/dga2005.pdf Small Steps to the Health and Well Being of America http://www.smallstep.gov/ Calories Burned Per Hour Calculator http://www.caloriesperhour.com/index_burn.php