Begin the lesson with the following comments: This past summer, NASA landed the Pathfinder space probe on the surface of Mars. What did scientists do before they even attempted such a mission? What are the difficulties they might have faced designing and constructing a vehicle to navigate a foreign landscape by remote control? Watch the video to see how one group of science students undertook their own "mission to Mars," following the same procedures as the NASA space scientists.
 

From that fateful day back in 1877 when Giovanni Schiaparelli trained his telescope on the surface of Mars and identified long, sinuous "canali," people have wanted to get a close-up look at the "red planet." It wasn't until July 1965 that earthlings finally got that first look, with the help of a remote probe called Mariner 4. Then in 1971, Mariner 9 produced pictures confirming that there were no signs of advanced life on the planet but strongly suggesting that running water and volcanoes had significantly reworked the surface.

In the summer of 1976, the Viking 1 and 2 spacecraft actually landed on the planet, taking the first color pictures and analyzing the soil for life. These two probes set the stage for the present round of exploration that culminated in the Mars Pathfinder and Global Surveyor missions in 1997. 

Mars is geologically similar to Earth. Large amounts of water once flowed over its surface, carving out deep channels and possibly forming seas in which primitive life existed. Mars also is home to Olympus Mons, the largest known volcano in the solar system (three times as tall as Mount Everest). Eruptions from this giant ended millions of years ago, but the findings suggest that Mars was once a warmer, tectonically active place. Even though the atmosphere on Mars is only about one percent as dense as Earth's, it still produces weather patterns. If all goes well, the Global Surveyor will provide us with detailed weather readings over the course of one Martian year (which is actually two Earth years).

In the coming years, NASA plans to send a number of additional unmanned probes to Mars to collect data on the ice caps and soil chemistry. Sending a spacecraft to analyze a planet that's 34 to 240 million miles away is a complex task, requiring an enormous amount of planning and teamwork. 

To get a taste of what it's like to be a Mars mission scientist, students from the Marcy Open School in Minneapolis created their own "mission to Mars." The first step in the planning process was to create a model of the planet's surface. The next step was to design a vehicle that could successfully traverse the landscape without getting stuck or, worse yet, falling over. The students tried rovers with different numbers of wheels, rovers of varying heights and widths, and rovers with different kinds of traction. After each test, design changes were made until the final working model was built. The last step was to create a computer program to actually make the system run. Once the program was "de-bugged," the class ran its model trip to Mars.
 

1. How are photos of Earth from space used to determine changes in our global environment? 

2. Recent advances in computer logic have made it possible for certain robots to "think." How might this be used in a space probe exploring the surface of a distant planet?
 
 

 Maps are really models of a place in space. A topographic map uses special lines called "contours" to show how the ground surface changes in elevation from one place to another. In most cases, when contour maps are made, the scale that is selected for the contour interval is proportional to the scale used to show distance across the map. In this activity, you'll discover what happens when you change the map scale but try to keep the contour interval the same.

Materials (per group of two students)
 
 

1. Discuss how topographic maps are used to show land surface features and how the scale for the elevation (contour interval) is usually proportional to the map scale. Note the scale used to calculate distance (1: 24,000) and the contour interval (usually either 10 or 20 feet).

 2. Use your ruler and pencil to mark off a 20-cm square on the topographic map. Take the first piece of paper and draw a 10-cm square. The object is to recreate all of the same contour lines that appear in the square on the topographic map by drawing them in the square on the paper. Since the square on the paper is half the size, your will have to "scale down" the space between the lines to half the distance. To do this, use your ruler to measure the distance between lines in millimeters and divide by two.

 3. Once you have completed drawing your half scale map, draw a 5-cm square on the second piece of paper. Follow the same procedures as in step 2, only this time, take the data off the 10-cm square. Make sure you draw in every contour line.
 
 

Questions

 1. Make a detailed contour map of your room or your classroom and do the activity again. Is it harder or easier to change the scale?

 2. What has happened to the spacing between the contour lines as you reduced the scale of the map? How did this affect your ability to read changes in elevations?

 3. When the scale is reduced on a map, what should be done to the contour interval? How does this affect the accuracy of the elevation readings?

 4. If you wanted to make a detailed map showing 1-foot elevation change on the surface of a planet, what type of scale would you need?