Science · Level 2 · 171 words
How Paste Joins Torn Paper
Original passage © Studio AM, written for Fluency.
At a paper-repair table, a thin paste can join torn fibers without hiding the page under thick glue. One traditional adhesive begins as wheat starch and water.
When the mixture warms, starch granules absorb water and swell. The cloudy liquid thickens into a smooth paste. A repairer brushes a small amount onto a strip of strong, thin paper and lays it across a tear. The wet paste reaches the tiny spaces among the paper fibers.
As it dries, water leaves the mixture. Starch molecules remain between the overlapping fibers and help hold the two papers together. Because the adhesive is water-based, a trained conservator can often soften it with controlled moisture if a repair later needs to be changed. That possibility is called reversibility.
The useful bond depends on care. Too much paste can stain or stiffen a sheet, and poor storage can spoil the mixture. In skilled hands, wheat starch paste provides a light, strong connection. Its science is quiet: water opens the structure, and drying leaves the adhesive behind.
Source: Written for Fluency. Original passage © Studio AM, written for Fluency.