Adhesive tape sticks because a soft layer flows into surface texture and resists being pulled away.

The longer version

Tape sticks for two reasons at once. Its soft adhesive layer flows into the microscopic roughness of a surface, giving a large real contact area, and the material resists being pulled away quickly because deformation inside the layer absorbs energy. Peel it slowly and it comes off more easily than a fast yank, which feels counterintuitive.

Adhesion depends on closeness; a dusty or greasy surface defeats it because the tape touches only the high spots, which is why cleaning first makes such a difference. Pressure-sensitive adhesives are formulated to stay tacky at room temperature rather than hardening like glue, and they weaken over time as the layer slowly creeps.

Where this entry sits

Odd Little Things looks at the ordinary objects people touch every day and the small mechanisms and histories hiding inside them. Buttons, zips, pencils, mirrors, stairs, stamps, packaging, and road signs all get their turn. The full list sits on the Odd Little Things page, where every entry is listed in order.