While experts debate about whether or not tablets and smartphones are appropriate for young children, the fingerprints all over your iPad are an indicator that children — some as young as 12 months of age — have taken the issue into their own hands.

Not to mention the 700+ apps aimed at toddlers in iTunes. Here are some apps with simple cause-and-effect relationships that curious toddlers crave.

Kid Tech Hardware and software for the newest users.

Keep in mind that you can get similar results with a tube sock full of beans, an old piano or a good-natured puppy.

Start with Moo, Baa La La La! ($2.99 for the iPad, $1.99 iPhone), which just might be the world’s first eBoard Book. Created by the children’s author Sandra Boynton, the app duplicates her printed book page by page, but adds self-narrating words, touch-animated animals and story-related skits, like a trio of pigs that sing in harmony.

Pat the Bunny ($4.99) offers more to do. It was inspired by the 1940’s children’s book by Dorothy Kunhardt, an author who glued things like sandpaper or fake bunny fur to the thick pages. This iPad edition has Velcro strips to fasten or unfasten, pages to fingerpaint and — if you have an iPad 2 with front-facing camera — the ability to see your own face in a mirror. You can also replace the narrator’s voice with your own.

When I asked parents for their tried-and-true toddler-app recommendations, ShapeBuilder ($.99 for iPhone) kept coming up. Despite being ancient (made in 2009 for iPhone), it works well on iPad’s larger screen, offering a set of self-correcting jigsaw puzzles with pieces that pop into place to make animals or letters.

Every baby likes to bang on piano keys, and app-equivalent experiences are easy to find. For example, both PianoBall ($2) and Sound Shaker ($2) turn your screen into child-friendly keys or buttons, creating a musical busy box good for exploring pitch, rhythms and harmony.

Finally, there’s now an app for the two words every young parent comes to know — potty training. Once Upon a Potty ($3), based on the Alona Frankel books have touch-and-hear labeling throughout, so your child can touch the diaper, you hear the word, and become more familiar with concepts like “a pee-pee for making wee-wee.” A potty song is thrown into the mix. There are boy and girl versions.