system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why can air be compressed but liquids can’t?
gpt
Liquids can be compressed, but significantly less than air (and all gases) can be compressed. It’s to do with the molecule structure. Compression forces molecules close together. In a solid, all these molecules are tightly packed together. So you can’t really compress, because there’s no room. In a liquid, there’s a bit more room, so you can compress it a little bit. Gases on the other hand have a lot more area to move around, and so you can compress them a lot more than liquids.