[AC Question]

I want them not to be able to access any inappropriate material

[B. Diddy]

Welcome to Android Central! Which device are they using? You'd probably have to install a browser with parental controls, like Net Nanny. Then you'd have to restrict their access to the regular browser, either by using an app like AppLock, or installing a kid-safe alternate launcher like Kids Place. Kids Place also has its own plug-in browser called Kids Safe Browser.

Next, be prepared for lots of eye-rolling and grumbling from your kids!

[Rukbat]

And be prepared for the two failings of this sort of app:

1) Appropriate (to you) sites that the app considers in appropriate will be blocked. (For instance, a site that mentions breast cancer awareness could be blocked because of the word "breast".)

2) Sites you consider inappropriate that aren't blocked because the people who write the app don't consider anything on the site inappropriate.

The only parental lock that works perfectly is a parent present when the child is using the computer.