Mars from Above: Carving Channels
Adapted from the Mapping Mars, Destination: Mars, NASA Johnson Space Center, 2002, and the Scratching the Surface unit of Explore!
Children ages 8–13 build water channels out of their observations of Mars and Earth as seen by satellites and orbiters in the activity Carving Channels.From these observations, scientists can draw conclusions about Mars' geologic past and its ability to support life, as well as how these features appear from space.
What"s the Point?
Collaborate with children to engage them. Developing critical thinking skills is essential. Create opportunities for spatial skills development.
These materials are for the station activity.
At each station, the following materials will be provided for approximately 8 children working in three-person teams.This station requires two "stream tables" (one per team):
Unless handled properly, diatomaceous earth is an inhalant hazard and can cause eye irritation.Use it in your stream tables but be sure to set up stream tables beforehand and cover the diatomaceous earth to keep it from becoming airborne when children are present.When setting up the tables and working with the diatomaceous earth, be careful.Make sure you wear a mask when handling the diatomaceous earth.If possible, wear gloves when handling this material, as it can dry the hands very quickly.
Each child must:
In the facilitator's words:
PreparationTray 1:.Tray 2:
Assume the following:.Examine the images of Mars and Earth.Spacecraft captured the images when they looked down on the planets.Rivers, streams, etc.Water.
Facilitator's Note: Early Mars was wetter and warmer than it is now.Scientific evidence strongly supports this contention.According to the data acquired by Mars orbiters, the ancient southern highlands are covered by dendritic drainage patterns - networks of stream channels known as "valley networks" which erode into highland craters.While there are some differences, these features are generally similar to the networks of gently meandering rivers on Earth.Various valley networks were interpreted to have formed on Mars slowly, which suggests that flowing liquid water flowed at or near the surface of the planet during a period in martian history.In orbit, chemical measurements reveal the presence of clays associated with some of these channels. Clays are formed when water has been present at some time.Mars Exploration Rovers have found evidence of liquid water as well.Water-carved structures in the rock were documented as well as minerals formed in salty, acidic water.
Here are two.Note that the trays and contents are known as stream tables, and they contain sand (and perhaps diatomaceous earth).The trays are positioned at an angle; one tray at a steeper angle than the other.Water— or any fluid— flows downhill.The water will flow downhill. It will create channel features much like the ones they observed in the images of Earth and Mars.Answers may vary, but may include that in the tray with a low slope, the water will travel more slowly. The size of the material may also cause a difference. Perhaps the sand will drain more.Answers will vary, but may include that the water will stop, or go around the obstacle.
1.2.3.Give the children the opportunity to create their own channels!
Four.Describe what the model means in terms of Earth and Mars.Look at the Mars matching cards and Earth image placemats to see how Martian and Earth features appear like meandering channels.In addition to its braided channels and teardrop-shaped islands, Mars has some other features similar to them.The water on Earth forms features like these.It means that the channels on Mars were likely also created by flowing water.Our observations can help us reconstruct what Mars was like in the past!
A list of Mars Cards (large file, 14 MB) and Mars Cards (small file, 2.8 MB)
Map of the Earth Placemats (large file, 23 MB) Map of the Earth Placemats (small file, 3 MB)
Consider what the children observed and the pictures from Mars and Earth.If they haven't yet done so, have them record what they learned on their Extreme-O-Files: Carving Channels activity pages.Water flowing across the surface cut into the surface and carried some of the material away.Flowing water carved Earth’s channels.No. Water carved the channels but the water is no longer there.
The facilitator may want to point out to the children that water may not be present in the channels in the stream table, but that the channels are still there as proof that water once ran across the surface.Channels can also be carved by another fluid besides water.On Mars, there is also evidence that water is most likely - ice caps exist near its poles, and soil is suspected to be a source of water as well.
Water— or another fluid!— created the channels. Water was once present.Mars once had flowing water that carved the channels, but there is no evidence of water on the surface today.All life as we know it needs water. If water is— or was— present, there may be— or have been— life!
Summarize the similarities between Mars and Earth in terms of their shaped by similar processes, and that both planets have stream channels.