IS THERE LIFE ON EUROPA?
A "PUZZLING" QUESTION

IS THERE LIFE ON EUROPA?
A "PUZZLING" QUESTION


Target Level: Elementary through middle school

Description: A game of chance involving gathering the ingredients for life and determining if life evolved by assembling a puzzle.

Objective: To learn about what is necessary for life (as we know it), the sources of the "ingredients for life", the role of large impacts in shaping life, and the difficulty of producing life even when the "ingredients" are present.

Vocabulary: carbon compounds, Europa, Galileo spacecraft, icy crust, asteroid and comet impacts, trilobite, extinction, evolution, diversity, satellite, Chixulub crater

Materials: one set of the 2 color figures; as many black and white copies of the 2 figures as the number of game sets desired; twelve-sided dice (as many as there are game sets, plus a spare); scissors, a razor a knife or paper cutter; twelve plastic baggies or large cups; a large flat surface; optional: poster board or foam core for mounting gamepieces; glue, paste or Photomount(TM) spray

Introduction: Life, as we know it, is known only on Earth. Earth is unique in our solar system in having liquid water on the surface. Although life is very diverse and can exist in extremely harsh environments, all life on Earth requires: 1) liquid water, 2) energy, and 3) carbon-based "building blocks". Two other worlds could contain liquid water beneath their surfaces: Mars and Europa, a satellite of Jupiter.

The Galileo spacecraft is taking images of Europa to search for evidence of liquid water beneath the ice. Because of the constant tugging on Europa by Jupiter and other moons of Jupiter, internal heat is generated within Europa (an energy source!). Carbon compounds are present in meteorites and (probably) comets, which have impacted Europa, providing carbon compounds, the third ingredient for life. But does that mean that life formed on Europa? One way to think of this is to compare the formation of life to baking a cake. You need flour, eggs, sugar and water for a cake. But just because you have the ingredients, combine them in a bowl, and add energy (an oven), doesn't mean you're going to get a cake. The ingredients must be carefully measured, combined and properly prepared. So it is with life. This game involves collecting three ingredients necessary for life, in abundances determined by chance (rolling of dice). If precisely the right amounts of these ingredients are combined, then life might result.



Teacher Notes


Set-up: The instructor should print out the two color image sheets, front and back, and have as many photocopies made as there are groups playing the game. One copy should be constructed and retained as a key to "winning" the game. Although color is preferable, black and white photocopies can also be used. After printing the sheets, paste the "key" sheets together back to back, so that there is an image of life (a trilobite) on one side, and the mosaic of gamepiece tiles on the other. This is the key to the puzzle. The key is especially nice if the sheets are pasted to both sides of posterboard or foam core. Repeat this pasting process with the photocopies.

Constructing the Gamepieces: The gamepieces need to be carefully cut out and paired in the same way as the key, so that they have a single "ingredient needed for life" tile on one side, and a piece of the "life has evolved" trilobite puzzle on the back. IT IS IMPERATIVE THAT THE PROPER PARTS OF THE PUZZLE ARE MATCHED TO THE SAME PATTERN OF GAMEPIECES THAT IS OBTAINED BY CUTTING AFTER MOUNTING! It can be very difficult to keep track of all the matching gamepieces if the sheets are pre-cut.

Before the Game - Discussion: Prior to beginning the game, it is useful to discuss the fact that the Galileo spacecraft is circling Jupiter taking pictures of Europa, that Europa is the second of the four large moons of Jupiter (just slightly smaller than our own Moon), and that the surface is made of water ice, beneath which there may be a liquid water ocean (see Web site: http://www.jpl.nasa.gov/galileo/sepo). Also, the ingredients necessary for life should be briefly reviewed, and the students challenged to think of examples on Earth where, for instance, oxygen isn't necessary for life, nor sunlight. A good example of both would be the "black smokers" where hot water issues from the deep sea floor, creating a unique ecosystem based on the chemical energy obtainable from minerals in the hot water. Tube worm colonies, etc., live in such places. The mass extinctions produced by large impact events, like the one that occurred on the Yucatan Peninsula 65 million years ago (Chixulub crater) and contributed to the demise of the dinosaurs, lead to diversity among the animals that survived (like mammals, after the dinosaurs were gone). Finally, water and carbon compound building blocks may have been delivered by impacting asteroids and comets.

Rules: One gamepiece can be obtained from the bin matching the number rolled on the dice. Students may not flip over the gamepieces to the life puzzle side during play. Trades of pieces must be one for one (see section Playing the Game below). Only twelve gamepieces are allowed per group, or participant, at the end of the game. Re-rolling may only be done at the discretion of the instructor. The winning group is the one that comes closed to constructing the entire puzzle.

Playing the Game: Each student or team should be given a twelve-sided die. The instructor then explains that the game involves rolling the die twelve times to obtain the ingredients necessary for life. Showing the completed puzzle is optional but useful at this point. The baggies/bins of gamepieces should be accessible to the instructor (for younger students) or the students themselves (older students). The die is then cast and the student or team obtains a gamepiece equivalent to the number rolled. In order not to run out of any particular gamepiece, the number of teams should not exceed 2/3 the number of game sets. It is still possible to run out of pieces (e.g., everyone may seem to be rolling a lot of 3s), and this situation can be remedied by having teams re-roll if they get the same number more than twice.

After each third roll (after rolls 3, 6, 9, and 12), student teams should be allowed to trade a gamepiece (one for one) with another team in order to have some of each of the ingredients for life. The instructor may even allow the students to see the arranged gamepiece key (not the trilobite side!) during play, so that the appropriate proportions of each ingredient can be sought out. It will still be difficult to obtain exactly the right combination, because there are multiple examples of each ingredient necessary, with different proportions of the trilobite on the back of each of the twelve gamepieces. After twelve rolls and the gamepiece trading described above have been completed, the students/teams turn over the gamepieces and attempt to assemble the trilobite puzzle in accordance with the key (now displayed by the instructor). Any team that has managed to acquire precisely one of each of the twelve gamepieces (a very difficult task, indeed) will have successfully produced life!

Typical Game Results: A typical game will last about 10 to 20 minutes, for 6 to 8 teams, depending on the age and enthusiasm of the students. For most games, the winner will be the group that comes closest to assembling the whole puzzle. Constructing the entire puzzle is quite rare. Ten out of twelve pieces right is excellent. Eight or nine is often sufficient to win, with 6 or 8 teams playing. By allowing more trades, or making other modifications of the instructor's own choice, the game can be made easier to win. Design your own customized version of the game and have fun!!!