•Find rays have same
 properties regardless of metal used in constructing the cathode.
  
 
 • Experiments show that cathode rays are made
 of charged
 particles that interact with electric and magnetic field when moving.
  
 
 • Particles are negatively charged (repelled
 by the negative
 plate, attracted toward the positive plate). 
  
 
 •These negative
 particles are fundamental particles of matter. Called 
 electrons. (1897 Thomson)
  
 •