Hard science
Hard science subjects include the natural sciences, which are about the natural world. These include physics, chemistry, biology, geology, astronomy, and botany. Soft science is any of the social sciences, including history, sociology, and political science. Those sciences are soft because something could be done more than once, and produce a very different result each time. Also, there are radical disagreements between various schools of thought. Some aspects of psychology are hard science, especially relating to perception.