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Abstract:

Working in a research group, students experience the environment of scientific collaborations in this series of investigations into high-energy cosmic rays. From start to finish this is a student-led, teacher-guided project. Schools with cosmic ray detectors can upload data to the web. A virtual data portal enables students to share these data and associated analysis code with students at other schools whether or not those schools have their own cosmic ray detectors.

To begin their research, students check the performance of the detectors they have chosen for their study. Then they can perform one of three investigations: muon lifetime, muon flux or extended air showers. Students can use the project milestones to conduct their research and can record their work and reflect on their progress in their e-Logbook. Students post the results of their studies as online posters. The real scientific collaboration follows. Students can review the results of other studies online comparing data and analyses. Using online tools, they can correspond with other research groups, post comments and questions, prepare summary reports and, in general, participate in the part of scientific research that is often left out of classroom experiments.

Read about the website features that guide and support student research.

Introduction to Research:

The Cosmic Ray e-Lab provides an opportunity for:

• Students to do authentic research using exploratory virtual data tools to access, process and publish data, report and share their results as online posters, and have online discussions with one another about their work.
• Student researchers to experience the environment of scientific collaborations.
• Student researchers to make real contributions to the study of high-energy cosmic rays.

Cosmic rays are typically protons, neutrons, gamma rays or other particles that originate in any number of astronomical objects. When these "primary" cosmic rays encounter earth's atmosphere, they can interact with nuclei of atoms and produce new, often unstable particles (e.g., pions and kaons). In turn, these secondary cosmic rays further decay and create muons, electrons, photons and neutrinos. If these cosmic rays are sufficiently energetic, they can reach the earth's surface and be detected. (Neutrinos are capable of passing through the earth and are generally undetected.)

Occasionally the primary cosmic ray possesses tremendous energy, creating many decay products. An array of detectors on the earth's surface can indirectly measure the energy of the primary by counting the number of particles in the detector array simultaneously. These observations can lead to a calculation of the part of the sky that the primary came from.

Prior Knowledge and Skills

Before doing this project, students should know how to:

• Make simple measurements.
• Make simple calculations.
• Interpret simple graphs.
• Write a research question.
• Make a research plan.

We provide refresher references for students who need to brush up on these skills. Students access these from "The Basics" section of the Project Map.

Learner Outcomes and Assessment:

Students will know and be able to:

• Content and Investigation:
  • Identify cosmic ray sources and describe how the resulting muons are created in the atmosphere.
  • Explain what the cosmic ray detector measures.
  • Manipulate the data in a way that helps them understand characteristics of the muon.
  • Design an investigation that asks a testable hypothesis, which can be answered from the cosmic ray data and provides a description of cosmic ray phenomena.
• Process:
  • Explain the data collection process including what corrections need to be made in order to obtain reliable data.
  • Evaluate the data to decide which are reliable/usable and which are not and explain how they arrived at the decision to include some data and exclude others.
  • Collect, organize and analyze data to obtain meaningful findings.
  • Use the data to provide evidence to support their claims.
• Computing:
  • Explain why they used specific computing resources in their analysis.
• Literacy:
  • Demonstrate an ability to express meaning in writing (such as in science notebooks, reports) and come to agreement about meaning with others (such as peer review, discussion).

Assessment is aligned to learner outcomes. While many teachers will want to design their own assessments, we provide some options.

• Rubrics: Content & Investigation, Process, Computing, Literacy and Poster
• e-Logbooks: Track progress and provide feedback on student work.
  Review students' evidence of what they know/understand and reflections on their research.
  Review all students' entries for a particular milestone, e.g., class cosmic ray descriptions, and make notes in your logbook for next year. Look at this sample logbook.
• Milestone Seminars: Check student understanding before they move from one section of the project milestones to another.

Research Question:

How much area can a cosmic ray shower cover? Where do cosmic rays come from? Students can pose a number of questions and then analyze the data for answers. Some answers are new to students but well answered by physicists. These include the muon lifetime, rate of cosmic ray arrival as well as the source of low-energy air showers. However, the origin of the highest-energy cosmic rays is an open question—scientists are trying to answer this question now. Students may be able to contribute data to these efforts. Many experiments have measured cosmic array showers, including CASA (Chicago Air Shower Array), project G.R.A.N.D. (Gamma Ray Astrophysics at Notre Dame) and the Pierre Auger Project (an array in Argentina).

Students will be able to look into the size of cosmic ray showers by comparing their cosmic ray detector data with that from others across a wide area to see where particles struck earth's surface in closely correlated time windows. (Data contain time and geographic location information.) Students will be a part of this ongoing research by providing data to a collaboration of their peers.