First, let’s talk about why open-source and free software is created.
Open source is software that is created using any number of licenses conforming to the official definition by the Open Source Initiative (OSI).
Free software is created exclusively using the GPL and the LGPL, the only two licenses that are acceptable and were created by the Free Software Foundation (FSF).
First, the two philosophies should never, ever be confused with each other. While open source includes the GPL and LGPL, and is a more inclusive philosophy overall, there are defining tenets of both that have caused strife between adherents of each.