Canals and Faces on Mars

For the Teacher

On the surface, this activity is about astronomy, but it is designed primarily to develop critical thinking skills. Hence it can be used in any class where critical thinking is important. Students should learn to apply their critical thinking skills to the wide barrage of information they will encounter in their daily lives. The historical example that is likely unfamiliar to students removes the problem of preconceived notions and allows concentrating on developing critical thinking skills. The more recent example allows students to evaluate a claim they may have heard of.

Adapt the activity to your situation by adjusting the sophistication of expected answers to your students' grade level. Students can do the research on the internet, in the textbook, or in the library. The activity can be assigned individually or in small groups. Make whatever modifications fit your situation.

Central Skill

Critically evaluating arguments that purport to prove or disprove some scientific point, to learn to distinguish between good and bad science.

Introduction

Pseudoscience, a generic term applied to very bad science, is also called voodoo science or pathological science. There are way too many examples from astronomy and other sciences. Often the ideas don't go away; they reincarnate in slightly different form. Examples include astrology, magnetic healing, scientific creationism, UFOs, crop circles, etc. Students need to develop skills to distinguish between good and bad science.

Canals and Faces on Mars

The canals on Mars make a nice example from the history of astronomy. In the 19th century an Italian astronomer observed what he thought were channels on Mars. He called them "cannali". This Italian word for channels has no connotations (in Italian) of man made structures; think English Channel rather than Panama Canal. However in English the word cannali evokes images of manmade structures. A wealthy American businessman (note: not scientist) named Percival Lowell got excited about the idea of canals on Mars.

In the early 20th century, Lowell built an observatory in Arizona to study Mars. He drew detailed maps of the canals and suggested that a race of Martians had built a planet wide system of canals to transport water from the polar icecaps to the warmer regions. Lowell even drew sociological inferences about the Martians from his observations - They must have a planet wide government. Lowell publicized his ideas and caught the public imagination, but other scientists did not see the canals. The issue was finally put to rest when NASA sent space probes to Mars in the 1960s and 1970s. Mars has no manmade canals.

Have students research this topic and write commentaries or have a class discussion. What led Lowell astray? Are there canals on Mars? What might he have seen that looked like canals? Don't let students get away with simply saying technology was not as good back then. The statement is true, but require more depth.

We are past that now right!

Have students google "face on Mars". Be sure they look at both at the original 1976 Viking picture showing the face on Mars and at the newer pictures showing the same area at higher resolution. They should also read both the official NASA sites and the sites claiming the face is evidence of a past civilization on Mars. Have them write a few paragraphs of commentary.

North Carolina's Grandfather Mountain and New Hampshire's Old Man in the Mountain, both resemble old men. Yet no one claims they are evidence of a past civilization. Is there a similar example in your location?

More Activities

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