fairfolio
Saved Projects

Is the Cosmic Ray Flux Greater at Higher Altitudes Than at Lower Altitudes?

CSEF · 2014 Physics & Astronomy First Award

Zoe Zawol · Sierra Madre Middle School, Sierra Madre, Los Angeles County

Overview

Objectives/Goals My objective was to to determine if the cosmic ray flux is greater at higher altitudes than at lower altitudes. My hypothesis was yes; I reasoned that at higher altitudes cosmic ray particles have a smaller chance of interacting with atmospheric molecules than they do at the increasingly denser atmosphere at lower altitudes. Therefore, the cosmic ray flux should be greater at higher altitudes than at lower altitudes. Methods/Materials To perform my experiment, I built a cloud chamber to detect cosmic rays. I lined a small aquarium (chamber) with felt strips soaked in 99% pure isopropyl alcohol. I sealed the chamber with a metal plate, inverted it, and placed it metal plate down on top of crushed dry ice. A supercooled alcohol vapor cloud developed within the chamber. Ionized cosmic rays passing through the vapor caused visible condensation trails. I tested my cloud chamber at different altitudes, video recording the trails. As a control, I placed the cloud chamber in an aluminum foil wrapped box, which I thought might block the cosmic rays. The videos revealed too many cosmic ray trails to accurately count, so I masked all but a small portion of the video screen proportional to a section of the cloud chamber. I counted the trails in that portion and calculated the cosmic ray flux per cubic centimeter per minute for each altitude. Results My results showed that at higher altitudes, the cosmic ray flux is greater than at lower altitudes. I reasoned that this is because the increasing density of the atmosphere provides more opportunities for cosmic rays to interact with other particles as they descend, resulting in fewer cosmic rays reaching the lower altitudes. I also found evidence that variations in the solar wind may affect the cosmic ray flux. Conclusions/Discussion My conclusion is that the cosmic ray flux is indeed greater at higher altitudes than at lower altitudes.

Summary statement

The central focus of my project was to determine whether the cosmic ray flux is greater at less dense higher altitudes above earth than at increasingly denser lower altitudes.

Help received

Dad helped me buy materials, drove me to the various altitudes to conduct my experiments, and talked with me about my ideas.

Awards (1)

Competition history

  • CSEF 2014 Physics & Astronomy · Entry J1829

Resources

Related projects

Closest projects by meaning, across every fair and year in the corpus.

Browse more like this

Source: California Science & Engineering Fair public projects

Save projects to your library

Sign in with Google to keep track of projects you find interesting, organized into folders. An account also raises your daily allowance for “Has this been done?”, and lets you create a key for the MCP server with a much higher limit than anonymous use. Browsing stays public.

Continue with Google