A good way to learn about maps is to make and use a map of a familiar area. For young children who may not have good spatial memory of their region, city, or even neighborhood, maps of the schoolyard can be the best way to approach teaching maps.
Maps are representations of an area as seen from above. This exercise introduces students to the view of their school from an airplane flying overhead. Students then make maps of their schoolyard by tracing over an aerial photograph that the teacher downloads from the web.
Making maps using this technique can take a bit of time, requires manual dexterity, and can be difficult if the aerial photograph for your school is not good quality. Teachers should try the activity out themselves and assess the suitability for their students. If it looks too tough, all is not lost! Provide your students with a blank map with the outlines of features from the aerial photograph and have them color it in and make the legend. The teacher completes steps 1-13 of the "During Class" instructions before class (without coloring). With students, begin the instructions at step 9.
|Introducing the Activity
Bring in a series of maps to show your students. These can be from the library, from your car, or from books and atlases. Try to get a variety of map scales and purposes (i.e., not all road maps). Ask students what these are and why people use them. See if they can identify the features that the maps share in common. What is different about them? The main goal is to get them to realize that maps show information about an area, that they have common features like scales and legends, and that they are interesting and pretty.
Ask students if they have ever made a map before (some may have made maps to buried treasures with their friends). Tell them that they are going to make a map of their schoolyard today. Remind them that maps are views of an area from above -- like what you would see from flying in an airplane. Then, pass out the air photos of their schoolyard.
| Before Class: (for the teacher)
- Follow the instructions about how to download an image of your school from Earth Explorer.
- Print the image out so that it covers nearly a full page. If you have a good photocopier, you can use its enlarge feature. Or import the image into WORD or POWERPOINT and stretch it out.
- Photocopy the image for your students. Check the image to make sure that there is enough contrast on the image to trace it through the tracing paper. If you can figure out how to enlarge the image in WORD or POWERPOINT, you'll find that directly laser-printing one copy for each student in your class produces a better quality image than most photocopiers. This can take a bit longer, but it will help students quite a bit.
- Spend some time exploring the aerial photo.
- Find features on your map: grass playing fields, blacktop play areas, buildings, surrounding roads, trees, bushes, play structures, sandboxes, or any other features that might be in your school yard.
- Point out shadows, if they are present. You might even be able to tell which features are tallest by the lengths of their shadows -- taller trees cast longer shadows than shorter trees in aerial photos. For high school students: You could even calculate the exact height of objects if you knew the time of day and time of year that the photograph was taken (so you could know the angle of the sun in the sky) using trigonometry.
- Optional: Notice that you can frequently see the sides of some buildings. This is because the photos are not taken exactly overhead of the schoolyard (An airplane is directly overhead a certain point, but it takes a photo of a wide area below it. You will only be able to see the top of a building located directly below the plane. However, buildings away from the center of the photograph are seen from a slight angle. You can demonstrate this with your students and a few textbooks. Place the textbooks on the ground so that they are standing upright (cover is perpendicular to the floor -- you may have to open the books slightly to keep them from falling down.) Line up two or three books about a foot apart in this manner. Have students stand next to the books so that their head is directly over one of the books. Instruct them to look straight down at the book. They should see the top of that book, but not its cover. However, they should be able to read the cover of books located just a little bit to the side. Imagine that these are buildings and not books.). The ability to see the sides of buildings is a feature of photographs taken from airplanes. Maps, however, are not photographs and you should never see the side of a building in a map.
- Place tracing paper on top of image. Carefully line up the tops of the two pieces of paper.
- The next step is easier if you work together with a friend. While you hold your papers in place, have a friend prepare a 1-inch long strip of tape.
- Have your friend attach the tape to the top edge of the top sheet so that about half of the tape is attached to the page and half is sticking off the end. Then, fold the tape over so that it attaches the two sheets together like a hinge.
- Do this again with a second piece of tape.
- You should be able to lift the tracing paper up to look at the image underneath without letting move when it falls down.
- Teacher tips about tracing: It may be hard to see through the tracing paper. Geologists use special tables called "light tables " that are made of glass and have a light shining up to make tracing easier. You can have the same result by taping your paper to the inside of a window. Geologists also use fancy translucent tracing paper called vellum that you can write on with regular pencils or pens (available from most office supply and stationary stores, but at about 20 cents a sheet it is fairly expensive). Overhead projector sheets, while clear, require special pens (usually too thick and clunky for map making) and are also expensive. Another hint is to use a dark pen to outline the edges of individual features on the paper photocopy first. Then they will show up better through the tracing paper. Features also show up better in color than they do on black and white photocopies, so project a color version of the image from a computer or overhead projector. Experiment with the photocopy of an image from your school to see what works best.
- Trace the outline of the image onto the tracing paper. This way, you can always align the tracing paper with the image in case your tape slips.
- Begin by tracing the tops of buildings. Only trace the tops, and not the sides because maps are what the world would look like if you were looking down from directly above it.
- Color the buildings in a certain color.
- Trace the outline of any grass playing fields. Color them green, or another color.
- Trace other features that you see on the schoolyard, using different colors when you want to.
- In the end, you should have a nice map of your school.
- Carefully cut the tape with the scissors to free your map from the image underneath.
- Every map has a legend -- this is the part of the map where you explain what each color means. For example, if you used green to indicate the color of grassy areas, draw a small green square at the bottom of your map and put the word "grass " next to the square.
- Every map should indicate which way is north. Aerial photographs from the National Map are all rotated so that north is towards the top of the page. Draw a compass rose on your map to indicate north.
- Every map also has a scale bar. While digital data downloaded from the National map include information about the scale of the photograph, there is an easy and reliable way to determine the scale of the map of your school.
- On your map, locate a feature in the schoolyard that will be easy to measure. For example, you can measure the tip-off circle in the center of a basketball court, the width of a parking space, the length of a building, etc.
- Go outside with your class and measure the length of that object with a tape measure. For the example school in the photo above, we measured the a basketball court tip-off circle and found that it was 4.0 meters wide.
- Return to the classroom and measure the length of the feature on your map using a ruler. On our example printout, it was 2.4 cm wide.
- To make the scale bar on your map, draw a rectangle the exact length as you measured with your ruler. The height of the rectangle doesn't matter. On our example map, we drew a rectangle exactly 2.4 cm wide and about half a centimeter high.
- Above the rectangle, label the bar by writing the length of the feature in "real life " -- the length you measured with a tape measure outside on the schoolyard. For our example, it was 4.0 meters. So every time something measure 2.4 cm on the map, it should measure 4.0 meters in real life. This is a good time to go over proportions in math problems!
Now the fun begins! Students can try to use their map. Start by asking simple questions about direction on the map:
"If you are standing at home plate, which direction do you need to travel to reach first base? " (north, south, east, west, etc...)
Once students master direction, have them try to measure distance. Start with questions about distance on the map:
"How far apart are home plate and first base on the map? Use your ruler. "
The hardest conceptual leap for students is to now convert map distance into distance in the real world. Using either mathematical proportions (older students), or creative use of their scale bar, they should be able to answer questions like:
"In real life, how far is it from home plate to first base? "