Organic geochemistry is all about studying the stuff that used to be alive, like plants and animals, and how it has changed over time. Scientists look at the chemicals that make up these once-living things and figure out what happened to them as they became fossils or oil.
Imagine you have a cookie. That cookie is made up of things like sugar, flour, and butter. Just like that cookie, everything that used to be alive is made up of different chemicals. When something dies, those chemicals can change over time depending on things like temperature and pressure. It's like when you leave a piece of bread out for too long and it starts to get moldy. The bread is changing chemically because it's exposed to air and moisture.
Organic geochemists study how these chemical changes happen, and what they can tell us about the past. They also look at how these changes can create resources like oil and gas, which we use to fuel our cars and heat our homes.
So, to summarize: organic geochemistry is all about studying what was once alive and how it changed over time, and figuring out what it can tell us about the past and our present-day resources.