How Does the Universe Work?
A Puzzle Analogy
This activity introduces the students to an interesting puzzle. A student worksheet and solution sheet
are provided. Suggest to the students that scientists have travelled to a distant galaxy and brought back these observations as part of their scientific investigations. The students' task is to propose a theory for what the basic building blocks in the galaxy are and what the rules are for how they connect. Be certain to clarify any questions about the shapes provided and the goals for students. Following this introduction and clarification have the students work in small groups to discuss their ideas. Finally, have the students present their theories to the class as a whole. Focus in on a discussion of strengths and weaknesses of each theory. One possible solution to the puzzle is included here, but remember there can be other valid theories. Finish with a discussion of what makes one theory better than another. Generally, if two theories explain the observations equally well, the simpler one is most widely accepted. This, of course, does not always mean the simple one is the correct one, but it may suggest a new generation of experiments.
This activity generally takes about one 55-minute period. You may want to break it up into two half periods on different days. If you do this, have the students write-up their theories as homework between the two days. These written assignments can be posted for the class, and students will be able to examine other student's ideas. At this point, the concept of publishing and peer review can be discussed.