The first method uses the keyboard; the second uses your fingers and the screen.
But if you hold your finger down on it, a menu pops up.
you’re free to actually pull it apart with your fingers.

Theaddition of the Virtual Touchpadto the keyboard iniOS 9makes this a little trickier.
If you engage the virtual touchpad, the iPad won’t recognize the gesture to split the keyboard.
It’s worth the update to the current iOS if you use this feature a lot.

This is accomplished by placing your fingers together and then moving them apart.
And because you are doing it with one hand, it can be easier for the iPad to recognize.
Method 1
Method 2
Push the keyboard together with your fingers on the screen.

This actually works a bit smoother than pulling them apart.
Simply place your index fingers down at the middle edges of each keyboard half and move your fingers together.