A correlation is a single numerical value that is used to describe the relationship between two variables. All correlations have strength and direction. When two variables have a positive correlation, that means the two variables move in the same direction. The closer a positive correlation is to 1, the stronger it is.
William Gilbert discovered electricity, not Nikola Tesla. Nikola Tesla invented things. not discovered electricity. Again, William Gilbert discovered it and named it. He did this in the 1600s. It wasn't Nikola Tesla.
Benjamin Franklin. Benjamin Franklin is perhaps the name most associated with electricity. In 1750, he sought to prove that lightning was caused by electricity by describing an experiment in which an electrical conductor would be used to extract power from a thundercloud.