system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What exactly is soap and why does it do a better job cleaning than straight water?
gpt
Soap contains stuff that helps make grease and oil "stick" to the water, so that when you rinse, the water rinses it away.   Water alone will take some of the grime away, but the soap enables it to get most, if not all of the grime.

Often, the foam and suds that you see when you use soap (or shampoo) actually isn't even necessary, but rather just something that companies add into the soap to make it "look" like it's working.