Why do Scientist do experiments more than once

Lets say your experiment is weighing an object. Lets say you do it only once. Lets say that this one time you measure the weight of this object, a fly lands on the object when you are taking the reading without you noticing.

What would happen in this case? Can you answer your question now?

If the Scientist would only run his variables once, he could say that he had absolute proof of what he wanted to prove. To honestly present his findings correctly and scientifically, he needs to verify that the answer he once obtained, can be duplicated and the same answer can be found. Of course there is a margin of error, but a very small margin.
Let's say the scientist presented his work and findings to a consortium of scientists. Those present should be able to take the experiment and duplicate all the parts of the experiment and come up with the same answer. That is why there are multiple studies done.

I remember my first psych experiment with baby chicks. And I thought I would never use statistics again, but I was wrong. Lol. I had to show that not just once, but in multiple trials, the findings were correct. Had I varied my technique, the results could have been different, faulty in fact.

So for a scientist, once is not enough. He (or she) would never be taken seriously in the science field. For example, look at the life of Marie Curie. She never settled for just once. Amazing woman and brilliant scientist.

Hehe lalla! That's part of the reason! But there's mush more important reasons for it.

1) reproducability
2) accuracy