The main aim of science is to gain a better understanding about the natural world and how it works. The base goal of science is to gain knowledge about why things are the way they are and how they got to be that way. An example of this might be scientists looking to understand how the Earth formed.
Science has also evolved with goals in which we work to apply the knowledge that we gain from science. For example, technology is developed and science is used to prevent certain things from happening or to predict what might happen in the future. We can use science to gain an understanding about how diseases develop and then use what is learned about these diseases to work towards methods to treat or prevent them.
An important component of science is that it is always evolving. Scientists are continually testing theories and looking to gain a better understanding of how things work. This goes back to the scientific method of creating a hypothesis and testing it, then replicating the experiment to continue to prove or disprove the hypothesis or determine which other factors might be involved.