1. Time Dilation and Length Contraction - The Evidence 1.Know how muons are produced in the upper atmosphere 2.Be able to explain the evidence from Rossi’s experiment regarding muon decay 3.Calculate the intensity of muons arriving at the Erath’s surface by allowing for time dilation

2. Collecting muons 2000m

3. What is a muon and where and how are they produced ? Muons are created when the cosmic 'wind' interacts with the upper atmosphere and when this happens they travel at a speed of 0.996c Muons are radioactive particles which decay to form either a electron or a positron together with a neutrino and an anti- neutrino Low energy muons have a half life of around 1.5μs at rest. When we make observations concerning muons moving at this speed there are two frames of reference that are important.

4. True or False