You can find an updated post with lots more ideas at https://inventorsoftomorrow.com/2017/03/16/touch-science-for-kids/
Textures table: We set up a table with fake fur, feathers, bubble wrap, pine needles, wool, and sand paper for children to explore. You could make your own sensory board. Just check Pinterest for LOTS of ideas.
Identify the texture: We didn’t do this in class, just due to logistics. But, you could blindfold a child, have them feel something, then guess what it was.
Texture gradients: Get several different grades of sandpaper. Have children put them in order from roughest to smoothest.
You could then have them use sandpaper to sand rough wood to smooth.
Tactominoes: These dominoes were in our classroom. I can’t find them to buy online – it looks like they might be from Discovery Toys in the 1990s. You could make something like them… In each circle, there’s different textures: sandpaper, corrugated cardboard, fuzzy felt, smooth plastic and so on.
Gather textures: On our outdoor hike, we asked them to touch a wide variety of things: rough Douglas fir, fuzzy red cedar, soft moss, serrated sword fern leaves, sharp holly, and so on. They gathered items from the forest floor that were interesting textures in a basket – lots of pine cones, some sticks, some dead leaves, and we took those back into the classroom to talk about more.
Art project: We did crayon rubbings. You can tape any textured but relatively flat object on the table, then kids can lay paper over it and do a rubbing.
Sensory bowls: You could fill several bowls with different sensory materials (rice, pinto beans, split peas, and so on) and have kids plunge a whole hand in and describe what they feel, then try another bowl and describe how it’s similar or different.
Use your sense of touch to “see”: Again, we didn’t have a chance to do this. But you could put items in an opaque container and have kids reach in, feel it, describe it and try to identify it. Optional: you could have pictures of items (or actual items) out on the table and have them reach in each container, and match the item they can feel with one of the items they can see. You can use obvious items (a spoon, an apple), less obvious items (a grape, a marble, a bouncy ball), or specific shapes (magnet letters).
Container options: something as simple as a pillowcase or a tube sock will do. You could also use a Pringles tube, put a tube sock over the end, and then cut a hole in the tube sock that they can reach through. Or a Kleenex box where they put hand in the opening without looking.
Temperature: You could have them explore temperature sensations by putting their hands in warm water and ice water. Or wrapping their hands around a metal container with ice water in it, and a coffee cup full of hot water. This would also offer an opportunity for a safety talk – when you think something might be hot, approach it slow and cautiously so your sensors can warn you if it’s too hot to touch!
Braille: In our classroom, we had some great resources we just weren’t able to fit into our one day on the senses. We have braille alphabet cards and a braille children’s magazine and more that would have been a fun texture exploration, but also an opportunity for education.
There’s lots more great ideas on Neuroscience for Kids.