Subreddit /r/askscience does a good job at explaining science in plain words. I usually google "site:reddit.com/r/askscience/ __QUESTION__". The StackExchange

Subreddit /r/askscience does a good job at explaining science in plain words. I usually google "site:reddit.com/r/askscience/ __QUESTION__". The StackExchange sites have less coverage and answers tend to be more technical. University websites return reliable answers, but often neither short nor accessible.