Drexel-SDP GK-12 ACTIVITY
Subject Area:
measurement
Activity Title: Measuring Distances with Satellites and Your Feet!
Grade Level: 6 (4–8)
Time Required: two 60 minute class periods
Group Size: 4–6
Expendable Cost per Group: none
Summary: In this activity, students are introduced to Google Maps, a collection of satellite
images with options for physical, political, and mobility map overlays. Students will use Google
Maps to locate an aerial view of their school. Using the map’s graphical scale, students will estimate
the size of various features (i.e. the dimensions of the school yard, the area of the block, the length
of the southern wall, etc.). Students will use Gmaps Pedometer to calculate the distance of various
routes through the local neighborhood. Finally, students will attempt to confirm their scale
calculations by physically measuring an outdoor distance on, and will compare their result with their
map-based calculations. They will further explore the concepts of using a two-dimensional scale
representation of a three-dimensional landscape surface, as well as unit conversion and basic
statistical treatments of data.
Engineering Connection: Civil engineers use satellite imagery to determine where best to
place roads, bridges, and other infrastructure. The images provide a birds-eye view of a location
without requiring the engineer to visit it. The imagers also display other useful information like
exisiting buildings, obstructions such as trees and large rocks, and utility poles.
Keywords: Maps, geography, scale, models
Educational Standards
Science: 3.1.7b, 3.1.7d, 3.2.7c
Pre-Requisite Knowledge: Students should have an understanding of direction (north,
south, east and west).
Learning Objectives
After this lesson, students should be able to:
• use internet resources (Google Maps and Gmaps Pedometer) to practice map skills and
concepts, within the context of their own school and neighborhood
• explore the mathematical relationships between objects of different scales
• correlate distances measured using a map scale bar with distances measured by the students
themselves
Materials List
Each group needs:
• a computer with internet access
• string (several feet)
• measuring tape/meter stick
Vocabulary / Definitions
Word
Definition
Model
A representation of a person or thing, usually at a different size scale than the
original
Legend
An explanation on a map explaining the symbols used
Symbol
A mark that stands for another physical object
Cartography The science and art of making maps
Surveyors
A person who examines and records the area and features of a piece of land
Elevation
The measure of how high something is, usually from sea level
Pedometer
An instrument that measures travel distance by counting the number of footsteps
taken
Physical
Maps that show physical features and landforms, such as mountains, rivers, and
maps
canyons.
Political
Maps that show local, state, or national boundaries, and often include major cities
maps
and capitals.
Maps that show travel routes along streets, public transit routes, etc.
Mobility
maps
Thematic
Maps that show data and statistics, such a population numbers, average
maps
temperatures, or annual rainfall, often with colors or shading.
Inventory
Maps that show the positions of specific buildings or objects, such as homes on a
maps
block, desks in a classroom, or stores in a shopping mall.
Maps that show the shape and elevation of land.
Topology
maps
Procedure
•
Introduction to Google Maps
Students should open a web browser and navigate to http://maps.google.com
2
•
Input the school’s address in the text box above the Search the map tab. A map of the
entered address will be generated. The default view is a moderately zoomed mobility map,
showing features such as streets and roads.
•
By increasing or decreasing the slider along the left edge of the map, students can zoom in
and out, respectively. Ask the students to increase the zoom to maximum magnification.
This should provide a clear image of the immediate neighborhood surrounding the school.
•
By toggling the buttons in the upper right corner of the map, students can switch between
the default mobility view (Map), a purely physical view (Satellite), and a cross between the
two (Hybrid). Allow the students to examine each of these options.
3
•
•
In some cases, the satellite imagery use to generate the maps may be out of date. In the map
examples shown here, a great deal of recent construction has taken place in the blocks
surrounding the school. Encourage the students to see if they can locate any out-of-date
features shown in the map image. This is an excellent foray into a discussion of the
importance of frequent updating in the field of cartography.
•
Ask the students to identify the scale bar on their images. This bar appears in the lower left
corner of the maps.
•
Using the scale bar, students should try to calculate the physical dimension of a feature on
their maps. For instance, the class might try figuring out the distance from one corner to the
next along the eastern side of the school building. This is more easily accomplished if each
student group can print out a copy of the map and measure the distance with a ruler.
•
Allow the groups time to make their measurements. Next, invite a student from each group
to write their measured distance in a chart on the blackboard.
•
After every group has reported their measurement, ask the class to consider reasons why
different groups may have arrived at different measured distances. This is an ideal
4
opportunity to discuss how measurements are subject to error. If the appropriate
mathematical concepts have been covered, the students can calculate the average distance, as
well as more advanced statistical features like the mode or standard deviation. The students
should be introduced to the concept of replicate measurements – that is, duplicate
measurements of a single property (in this case, distance) made for the purpose of
minimizing random error.
•
•
At this point, allow the students to explore Google Maps on their own. Encourage them to
look for other landmarks in their city, as well as in other places around the world.
Generating directions and routes
Google Maps has a function to calculate directions between to points. By selecting the Get
Directions tab above the map, students can input two addresses (a starting and an ending
point). A series of verbal directions will be generated, along with a map with a route overlay.
•
The Get Directions feature of Google Maps is useful for finding common, direct routes
between two points. However, students can calculate more complicated and circuitous
routes using the Gmaps Pedometer, located at http://www.gmap-pedometer.com (note
that the web address has the word “gmap” rather than “gmaps”).
•
Remind the students that a real pedometer is a device that makes a measurement of
distance traveled on foot, by counting the number of steps taken (many walkers and runners
use pedometers while exercising).
•
Students should first find a map of interest and zoom to a comfortable magnification level.
To begin measuring a route, they must click the Start Recording button on the left of the
screen.
•
To mark the start of the route, double click on the map image. A red marker will appear
on the map. Double click on the next location along the route to place another marker.
5
Continue placing markers along the route of travel. The total distance will be constantly
updated on the left of the screen.
•
Verifying measured distances on foot
Now that students have used a scale bar to calculate a physical feature on a Google Map, and
are now familiar with the concept of a pedometer, they are ready to combine these two
concepts!
•
Each student will first measure the average distance they travel with each footstep at a
normal gait. To make these measurements, students must work cooperatively in small
groups. Each student will take five “normal” steps, and the other members of the group will
track the distance traveled using a length of string. The string will be measured using a ruler
or meter sticks, and the average distance traveled per step will be calculated by dividing the
total distance by 5. Remind students that by taking the average of several replicate steps,
the error associated with slight variations between steps can be minimized.
•
Once each student has determined his or her average distance per step, the class is ready to
make their pedometer distance measurement! Gather the group at the starting point, and
walk together to the ending point (for example, from one corner of the block to the
opposite corner). Each student is responsible for counting the number of steps he or she
takes.
•
Once the voyage has been made and the students have returned to the classroom, have them
immediately convert their footsteps to a distance. For example, if Johnny travels a distance
of 0.6 meters with each step, and took 195 steps from one corner to the other, his calculated
distance is:
meters
0.6
× 195 steps = 117 meters = 0.117 kilometers
step
•
Once again, have the class compare their calculated distances, both against the “footwork”
of other students in the class, and against their calculations made using a printed map and
scale bar.
Assessment
Pre-Activity Assessment
6
This activity is an ideal practice not only of map skills, but also of mathematic conversion and basic
statistical analysis. Students should keep a careful record of their own measurements, as well as
those shared by the class, in their science journals. They should be able to demonstrate proficiency
in making appropriate conversions (for example, between the length of a scale bar, in centimeters,
and a distance on the map, in meters or kilometers). They should also be able to convert between
metric and English units of measure, given the appropriate conversion factor (i.e. 1 mile = 1.61 km).
As an advanced extension to this activity, students can be introduced to recording data in a
spreadsheet. Using Microsoft Excel or a similar software package, the class can be guided in the
construction of a graph to represent their data.
Most importantly, emphasis should be placed on the idea that measurements have some inherent
degree of error and uncertainty. By looking at the overall trends of an entire pool of data provided
by each member of the class, rather than focusing on the results of a single individual, it is hoped
that random error may be minimized and a more accurate, averaged result can be arrived at.
Activity Extensions
Students can also make use of a tool to calculate area from Google Maps. The Google Planimeter
website at http://www.acme.com/planimeter/ allows students click on at least three points of a
map to calculate the area of the enclosed triangle. By clicking on additional points, the triangle is
expanded to a polygon. The more points the students ad, the more detailed the shape becomes.
Redirect URL:
http://gk12.coe.drexel.edu/modules/doc/Matthew%20Cathell/maps%20module/Maps%2
0Module.pdf
Owner: Drexel University GK-12 program, Engineering as a Contextual Vehicle for Science and
Mathematics Education, supported in part by National Science Foundation Award No. DGE-0538476
Contributors: Matthew D. Cathell
Copyright: Copyright 2007 by Matthew D. Cathell
7