free software is like a public park where anyone can enter, and use the facilities.

- until park officials change their mind.

Open source software is like a community garden – individuals work together to cultivate and enhance it, sharing the fruits of their labor with everyone.

Open source software has a publicly available programming code so that it can be audited and you know what the software does under the hood. So you're not likely to have sneaky spyware/malware included.

Free software just means that you don't pay directly for it but it could be closed source or open source.