Your baby is becoming very handy. Although she's already aware of her hands, she's now inspecting them like Sherlock Holmes. She turns them around, the better to look at her fingers from all sides. She opens and shuts her fist, watching each finger as it moves up and down. It's almost as though she's using her hand like a puppet and putting on a private show. To help your baby develop her blossoming hand-eye coordination, try dangling a toy just out of reach so she has to grab for it.

Your baby will also place a finger or as much of her whole hand as possible into her mouth. That's another way she's learning about her hand — its textures, how big it is, and what it tastes like. The hand is, well, handy for exploring this way because it's right there in front of your baby and never gets lost. But eventually, you'll find she's discovering all sorts of things around her as she puts them into her mouth. This is an important way for babies to gather information about their world (and a time for you to make sure yours can't put anything into her mouth that will cause her to choke).

From babycenter.com