Many people thought the first probes to land on the surface of Mars-Viking I and Viking II-would discover
little green Martian men or some other form of extraterrestrial, so there was much disappointment when no
signs of life were spotted. Below is an experiment similar to the tests the Viking probes performed on the
Martian soil in search of life on the Red Planet.
- Fill each glass one-third full of sand.
- Number each jar.
- Measure two spoonfuls of salt into #1, two spoonfuls of baking powder into #2, and two spoonfuls of yeast into #3.
- Refrigerate the jars overnight, so that they are cold like Mars.
- The next day, mix a half cup of sugar into a pitcher of warm tap water. Pour equal amounts of sugar water into each of the jars.
- Look for signs of life! What happens in each of the jars?
The Viking experiments added nutrients to Martian soil samples and monitored the reactions-a brief, quick reaction
indicated the presence of non-living chemicals, while a slow and continuous reaction would suggest that a life-form
was multiplying. In your experiment, which jar contained something living? The question of life on Mars is still
being pursued. Instead of looking for huge plants or animals, scientists have now turned their search toward the
possibility that microscopic bacteria may live-or may have once lived-on the Red Planet.