Don't waste hours looking through websites trying to find the ones that are kid-friendly. Today I came across a search engine just for kids called KidRex. While no filter is 100% accurate, this is a great place to start.
I typed in "alligators" and up came several sites to help kids learn about alligators. There were pictures, facts, videos, information, lessons, and so much more.
Of course, this site is great for teachers and homeschoolers. If you're looking for a site on a particular topic, just type it in, and you won't have to surf through all the other junk.
Give it a try and let me know what you think.