Differentiating between rough and smooth surfaces is a very common practice in our daily lives. Incorporating the Montessori touch tablets I came up with these.
I bought these small wooden boards from the $ store, and stuck a low grade sand paper on one. Lil Muallimah got to sense rough and smooth by rubbing two fingers on each board.
You can see the video for touch boards at ehow.
I added a variation to this activity by keeping a different surface objects in a tub next to the tablets. Lil Muallimah feels each object with her hands and decides if they should go under the smooth surface board or the rough surface board. I plan on using different things from time to time. Like shells, rocks, vegetables, fruits, leaves, toys etc.