Body Proportions Sequence

Topics: Measuring, rounding, graphing, scaling, categorical data,

Focus Questions

1. Is there a mathematical relationship between heights of different body parts?
2. How do people chart values when the numbers are larger than the number of squares on a piece of paper?
3. What is a rounded number and how do mathematicians decide how to round numbers?

Concepts

Problem solving, communication, connections, reasoning and proof, and representation,

1. Relationships can be expressed mathematically.
2. Measurement is used to communicate information more accurately.
3. A chart represents certain values.
4. Procedures can be supported with proof.

Numbers and operations, geometry, algebra, measurement, and data analysis and proof

1. Number value of similar increments are proportional (e.g. the number of increments between a person puts between 2 and 3 can be put between 4 and 5 …)
2. Five is mid way between 0 and 10.
3. When using a ruler or number line you count the spaces.
4. Numbers are rounded according to the precision needed.
5. All measurement is an estimate.
6. Information can be grouped into categories. Numbers are rounded to group values by categories.
7. Information that is scaled maintains its value and proportions.

Background

Students will measure different points on their body (point on right ankle, top of right patella, top of right hip on the side, top of shoulder blade, top of head.) and chart the data. Points on the body are picked to create at least two problems: first a small number (ankle) that hopefully some will need to be rounded to zero and second a large number that would require that the values be scaled to fit on the chart (shoulder, head).

Activity Sequence

1. Measure student body parts
2. Record them on a class cart.
3. Chart them on jumbo class chart (one to one not scaled).
4. Discuss what to do with values that don't fit.
5. Scale by tens.
6. Round numbers.
7. Chart on chart scaled to ten.
8. Review what learned.

Activity Descriptions

1. Ask students what the average height of a fourth grader is? Ask if they think that the distances from the floor to different people's ankles, knees, hips, shoulders are different? Ask them if they think that there might be a pattern between the heights.
2. Have everyone find the same points on their own ankle, knee, hip, shoulder, and head.
3. Show them a metric ruler and ask them if they know how to use it.
4. Have a student demonstrate how to measure the height from the floor to the bottom of the chalkboard. Have the other students critique the procedure used.
5. Pair students, have them measure each other, and record the distances, in cm, on a chart provided.

1. Create a chart with numbers 0,1,2,3,4,5,6,7,8,9… for as far as the chart goes. However, make sure that the chart will not be large enough to include any of the student's shoulder measurements.
2. Provide students with five different colored dots.
3. Have each student put their green dot on the chart in the proper location.
4. Chart with numbers 0,1,2,3.. up the left side (y axis) and each student's name across the bottom (x axis). Write a title across the top (Fourth grade student's body parts heights)
5. Continue until all ankle heights are placed, then pick another colored dot and have them chart the patella and so on until they run out of room or a student claims they will run out of room.
6. Ask students what they should do? Students may want to just stick them on the wall above the chart. If so allow them to do so and finish the charting.
7. Lead or introduce them to the idea of scaling the numbers. Suggest that there is another way the mathematicians could have solved the problem.
8. Bring out a new chart that looks the same only the numbers in the y axis are 0, 10, 20…
9. Ask them if they were going to put their measured number into one of the following boxes (0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110…), which one would it be and their reason why.

1. Have them report their decisions and their reason why.
2. Ask them if they can see a pattern to how they organized them. If not, then ask them how they could rearrange them so that there was a rule and all would know what box to put them in.
3. Have them refer to a hundreds chart, number line, or metric ruler to give reasons to support their answers.
4. When they agree on what rules give consistent solutions, have them use it/them to put their dots onto the chart with the multiples of ten.
5. Have students compare the second chart with the first.

   ***** Depending on student interest 19 or 20 could be interchanged.******

6. Review the rules that they created. Have them use it on different numbers (3, 15, 26, 34, 65, and others desired) and illustrate it on the hundreds chart and that
7. Have the students look at the chart and see if they can find any patterns between students and between the measurements of different body part heights. One relationship would be that all increase in value. If students place their dots in order height, do the distances between each person's body parts and another person's body parts increase proportionally?
8. Ask them how else they can use what they learned. When would they want to round numbers? When could they make a graph to solve a problem? When would they need to scale their data. Does scaling their data change the results? Why or why not?

Robert D. Sweetland's Professional Notebook ©