Science abstracts are like little summaries of big and important science projects. They're kind of like if you took a whole book and squished it down into just a few sentences. Scientists use abstracts to help other people understand what their research is all about without having to read the whole big paper.
The people who write abstracts have to be really good at picking out the most important parts of their work and explaining them in a way that anyone can understand. Imagine trying to explain a really complicated game to your little sibling – that's kind of what writing an abstract is like.
When scientists finish a big project, they write a paper telling everyone about what they found. But not everyone has time to read the whole thing – it might be a hundred pages long! So they write an abstract that says what the project was all about, what they did, and what they learned.
That way, if someone wants to learn about the project but doesn't have time to read the whole paper, they can just read the abstract and get the basic idea. Cool, right?