Scientific Investigation: This case begins with the generative question or idea: Is there a water cycle on Mars? This case was inspired by the recent press release from the NASA's Phoenix Mission on Mars reporting preliminary evidence of snow falling from clouds in the north polar region and other evidence for the presence of water on Mars. Teachers developing the instructional case will examine data related to the question of water on Mars and refine their investigation to more specific questions that will help to answer the generative question:
- What is the evidence that there is water on Mars?
- Does it precipitate on Mars?
- Where is the water on Mars?
- Is there a water cycle on Mars similar to Earth's water cycle?
- What is the role of water in possible life on Mars?
More fundamental questions such as those posed above that relate to the nature and occurrence of water on Mars can be addressed by examination of these data and more. In addition, teachers may connect this investigation to more foundational science content that is common in high school science courses such as phase transitions (sublimation, melting, etc.), vapor pressure, solution chemistry, and the unique properties of water (polar molecule, low density solid, etc.).
Since water is an essential component required for life as we understand it, then demonstrating the existence of water on Mars is a key step in determining whether life exists or existed previously on Mars. While images of clouds, ice and geologic features that are the result of the action of liquid water on Mars are an important piece of evidence in support of the existence of water on Mars, it is still critical that scientists are able to use the unique capabilities of the NASA missions such as the Mars Phoenix probe to develop additional evidence for the existence of water on Mars. The challenge for students will be to identify experiments that could be conducted remotely that would demonstrate the existence of water on Mars and then carry out those activities within the classroom.
Activities related to this instructional case must include hands-on laboratory experiments that emphasize the experimental nature of science. For example, teachers and students may develop tests that could be used to confirm the presence of water on remote and hostile environments such as Mars. These laboratory experiments may be viewed as developing analytical capabilities for future NASA missions and may include:
- Measuring the freezing point of water
- Measuring the boiling point of water
- Chemical reaction with CoCl2 indicator paper
- Measurement of pH
- Dissolution of ionic compounds such as common salts
- Electrolysis of water to produce component elements O and H