Because you cannot see internal changes within an electron. It is a fundamental particle which means it cannot be broken down further and is "indestructible" as the atom was originally theorized to be by the Greeks. It moves so fast that it appears to be in all places at once looking more like a wave than a particle and is still subject to quantum mechanical effects (like quantized spin) which also affect its actions. That's why they refer to an electron cloud and its orbit. It travels so fast it is literally in every point within its orbit at almost the same time.
what i meant was, because objects that move close to the speed of light are seen by outside observers to be in slow motion. why are we not able to see electrons that appear to be moving in slow motion?
What would you look at to tell if the electron was going in slo-mo? Its velocity? You just said it was moving fast. Besides, how are you going to "see" an electron without changing it? Can't use photons, because they'll be absorbed and reemitted.
You misunderstand what is meant by "moving in slow motion". The concept your wrestling with states "if an electron moves at the speed of light, then it should appear to be moving at 10 miles an hour". That's a contradiction. If it's moving at near the speed of light, it's moving at near the speed of light. Time dilation affects INTERNAL time. If we look at a spaceship, nothing is obviously different about its speed and trajectory; however, look INSIDE the ship and everyone appears to be moving in slow motion. The only way we see this in a particle is by measuring its lifetime. I believe that one of the proofs for relativity was in explaining how a muon made it into the earth's atmosphere from the sun. We are 8 light-minutes from the sun and its lifetime is 7 minutes meaning it would need to travel faster than light to make it here. That's impossible! However, taking into account its relativistic speed and calculating the time dilation for the muon, it actually was "aging" slower and extended its lifetime several minutes, more than enough to make it into our atmosphere before decaying.
<This message has been edited by Victor S (edited 05 November 2000).>