Gel
A colloidal system in which a liquid is trapped within a continuous three-dimensional solid network.
Unit
Dimensionless
In depth
Although a gel may be more than 99% liquid by mass, the interconnected solid framework makes it behave as a soft solid that holds its shape. Gels can swell by absorbing more liquid, and many are thixotropic, liquefying when shaken and resetting when left undisturbed.
Examples in the real world
Gelatin dessert, silica gel desiccant, agar plates, and the hydrogel in contact lenses.