Imagine you're looking at a picture of a tree. If it looks like the real tree, with every leaf and branch, that's realistic. But if the tree is just squiggles, colors, and shapes that don't look like anything else, that's abstract.
The Magic of Realism
A realistic painting tries to copy the world exactly, like a mirror. You can see all the details, the texture of the bark, the shine on the leaves, or even the way the light hits them.
The Freedom of Abstraction
An abstract painting uses colors and shapes to show feelings or ideas, not real things. It's more like a dream than a picture you'd find in a textbook.