An observational study is like being a detective and just watching things happen without trying to change anything. Imagine you and your friend sitting on a park bench and just watching people walking by. You do not stop anyone or ask them questions, you are just watching what they do.
In this case, you are observing people and their behavior. Similarly, scientists use observational studies to learn about how things happen in real life situations. They watch and collect information about people, animals, or things to understand how they behave or what they are doing.
Observational studies are used to help scientists understand different things, like how animals behave in the wild or how people use technology. Observational studies are usually used when it would be difficult or impossible to control everything that is happening in a situation.
Overall, the main idea is that scientists watch and collect information about things in natural settings to gather information about how they behave, and use that information to learn more about what they are studying.