Asked by: Hazel D'Arcy, Kent
Blu-tack uses a so-called electrostatic interaction, forming a chemical bond between itself and whatever it's sticking to. It's made up of very small molecules and, over time, seeps into microscopic indents in the surface of materials. The electrostatic interaction gradually gives way to that molecular 'seeping'. Hence Blu-tack doesn't feel sticky initially, but gets stickier if you handle it long enough.