Sandpaper Only Works If It Is Rubbing Against Something

Feld Thoughts

Shark skin (placoid scales) has also been used as an abrasive and the rough scales of the living fossil, Coelacanth are used for the same purpose by the natives of Comoros. I recently heard the line “sandpaper only works if it is rubbing against something” and loved it. From Wikipedia: “The first recorded instance of sandpaper was in 1st-century China when crushed shells, seeds, and sand were bonded to parchment using natural gum.

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