... Astronomy . ... Requires various plug-ins to your browser to work right. [m,h] (A simpler version of this activity, to be done with printed paper versions of the image, can be found at: www.jpl.nasa.gov/galileo/sepo/educaton/europa/puzzle.html ) . ... Interesting activity, in which students use an inexpensive "stream tray" to simulate the flow of water on sandy terrain, compare their results to features seen in martian images, and then try to replicate some of the features seen on Mars. ...