How do we know what we know about electrons if they are so tiny?

I should start by saying that electrons are 1/1836 of the amu of an atom.  That is really small!  Obviously an atom can not be seen by the naked eye so humans use microscopes.  The first microscope was invented in 1590 by a group of eyeglass makers in the Netherlands.  Since 1590, microscopes have become much more advanced.  In fact, some microscopes have been developed specifically to show atoms.
            Microscopes are only one way to show electrons.  Scientists have performed a great deal of experiments that have shown us most of what we know about electrons today.  One example is J. J. Thomson's Cathode Ray Tube.  The Cathode Ray Tube was a glass tube that had a device inside of it that emits a cathode ray (an electron beam) which was invisible but emitted a glow at the end of the tube. Thomson theorized that electrons were negatively charged so he placed a positive electric magnet on the bottom of the halfway point of the tube. When the beam was emitted it bent towards the magnet moving the glowing point down. This proved the existence of electrons.
             There are many other experiments that demonstrate what we know about electrons today but this is a good example of one.  The Cathode Ray Tube: