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.
Alessandro Volta invented the voltaic pile in 1800 thereby producing the first practical method of generating electricity. The voltaic pile was made by alternating plates of z â¦ inc and copper that had pieces of cardboard soaked in brine between them.