There are many ways that scientists try and understand the dynamics of Earth. Some of my colleagues look at the chemistry of rocks on the surface of Earth or those brought to our planet in the form of meteorites to track the history of Earth and our solar system through time.
Others study the waves that come from earthquakes to image the inside of the planet, much like the way a CT scanner works, or measure how different materials behave at the high pressures and temperatures inside our planet.
I, myself, am a theorist, which means I try and use the laws of physics and chemistry to build models of the processes that have shaped, and continue to shape, our planet, using all my colleagues' work to constrain my calculations. Sometimes, this requires me to just sit down with a pen and paper and work through some math [and], at other times, to use some of the most powerful computers in the world. Most importantly, I spend a lot of time talking to other scientists, bouncing ideas off each other, and combining our knowledge to understand the workings of our dynamic planet.