Benjamin Franklin conducted experiments with electricity in the 1700s using simple apparatus. Through his experiments, he developed the concepts of positive and negative charges and proposed demonstrating the connection between lightning and electricity by flying a kite during a storm. In 1752, Franklin performed his famous kite experiment during a storm and was able to draw sparks from a key attached to the kite string, providing evidence that lightning is a form of electricity. Franklin's experiments made him famous and helped establish the field of electrostatics.