What a good question! Social action is when you do something to help someone else out or to better society. Things like volunteering in a soup kitchen or going to a third-world country to help provide clean water would be considered social action. Social interaction is simply spending time with people and doing things in a social setting. It often refers to how people communicate to each other in social settings.

Social action means making a change to society in order to improve it. Social interaction is simply communicating with other people.