The "Pi in the Sky" math challenge gives students a chance to take part in recent discoveries and upcoming celestial events, all while using math and pi just like NASA scientists and engineers. In this problem from the eighth set, students use the mathematical constant pi to determine the force observed by a hydrogen ion trapped in Earth's magnetic field. Materials Pi in the Sky 8: Force Field worksheet – download PDF Pi in the Sky 8: Force Field answer key – download PDF (also available as a t