For this experiment we wanted to explore sandpaper. We learned about its uses, and how it is made.
I gave each kid three sandpaper squares in different grades: fine, medium, and coarse. They felt them, and looked at them with the microscope. They pointed out the little rocks in them. We also talked about the different sizes of rocks.
They placed paper over the sandpaper square, and using crayons rubbed it to record the sandpaper texture. They challenged each other to identify each sandpaper grade by feeling them with their eyes closed.
We turned the sandpaper sheets over, and looked at the grade number for each one. We discovered that fine sandpaper has a higher number than coarse sandpaper. We deduced that it meant the amount of rocks included in a specific piece of sandpaper. If the rocks were larger in size, it had less of them. This made the sandpaper rougher resulting in coarse paper. The smaller the size of the rock, the larger the amount of rocks making it very fine.
Then each kid got a piece of wood and compared what each grade of sandpaper could do. We learned that coarse sandpaper gives more dust, and takes more wood. Fine sandpaper is very gentle and can be useful when getting details in the wood.