You can study both the history of science (such as how the scientific method evolved) and the impact of science upon history, but perhaps the most human aspect of the subject is in the study of scientists themselves. This list of notable scientists is in chronological order of birth.
Charles Darwin
Bain News Service / Library of Congress
The father of arguably the most controversial scientific theory of the modern age, Darwin was born in England in 1809 and first made a name for himself as a geologist. Also a naturalist, he arrived at a theory of evolution through the process of natural selection after travelling on HMS Beagle and making careful observations. This theory was published in On the Origin of Species in 1859 and went on to gain widespread scientific acceptance as it was proved correct. He died in 1882, having won many accolades.
Max Planck
Bain News Service / Library of Congress
Planck was born in Germany in 1858. During his long career as a physicist he originated quantum theory, won the Noble prize and contributed greatly to a number of areas including optics and thermodynamics, while quietly and stoically dealing with personal tragedy: one son died in action during World War 1, while another was executed for plotting to kill Hitler in World War 2. Also a great pianist, he died in 1947.
Albert Einstein
Library of Congress
Although Einstein became an American in 1940, he was born in Germany in 1879 and lived there until being driven out by the Nazis. He is without doubt the key figure of twentieth century physics, and probably the most iconic scientist of that era. He developed the Special and General Theory of Relativity and gave insights into space and time which are still being found true to this day. He died in 1955.
