From site:  This site has an introduction to the earth sciences that includes topics on the Earth’s structure, atmosphere, hydrosphere, and biosphere (for a start)…

Many of you may not be familiar with PHYSICAL GEOGRAPHY. It’s the biggest EARTH SCIENCE around. It uses many ideas from other sciences that you have seen before. We can only begin to explain how ideas from many different fields combine into the knowledge of physical geography. You will find information from chemistry, biology, physics, climatology, astronomy and many other sciences.

One big thing to remember… This kind of geography is not about countries and gross domestic products. Physical geography is all about the Earth and the things that happen on Earth. Humans are only one part of the overall equation.