Thomas Edison we all know was a great inventor and entrepreneur. He invented many useful things like gramophone and camera but his most popular invention was the light bulb which we use till today. Here is one interesting and very useful piece of information about his invention of the light bulb.
Edison had developed the theory on which the light bulb would work but he could not find the right material to be used as the filament in the bulb. He tried two thousand different materials in search of a filament for the light bulb. When none worked satisfactorily, his assistant complained, “All our work is in vain. So many years of trying and testing and we have learned nothing.”
Edison smiled and replied very confidently, “How can you say that? We have learnt so much!”
The assistant asked, “What do you mean, sir?”
Edison said, “After having spent all this time in getting the right filament, we know that there are two thousand elements which we cannot be used to make a good light bulb! Even when we fail, we learn something!”
Source: Real life