absorbs

Absorbs is the third-person singular present tense of absorb. Absorb means to take in or soak up something into the interior of a substance or system. In everyday usage, a sponge absorbs water; in science, materials may absorb light, heat, or sound, and tissues may absorb nutrients and medicines. Absorption is often contrasted with adsorption, where molecules adhere to a surface rather than enter the bulk.

In physics and chemistry, absorption is the uptake of energy by a medium. Light absorption depends on the absorption coefficient and helps determine a substance’s color; the Beer-Lambert law relates concentration to light absorbed. Thermal absorption describes how materials gain heat, and in acoustics, some materials absorb sound energy to reduce reflections.

In biology and environmental science, absorption describes uptake across membranes and barriers. Nutrient absorption occurs in the digestive system as substances pass into the bloodstream. Gas exchange organs absorb oxygen and release carbon dioxide. Plants absorb water and minerals from soil through roots. In ecology and environmental monitoring, soils, sediments, and organisms absorb pollutants, influencing transport, persistence, and bioavailability.

Measurement and terminology. The term absorption is distinguished from adsorption; absorption implies penetration into the interior, while adsorption is surface binding. Quantitative descriptions use absorption coefficients, diffusion rates, or permeability; units include per centimeter (cm^-1) for optical absorption and square meters per gram (m^2/g) for material absorption capacity. The concept appears across disciplines, from spectroscopy and pharmacokinetics to hydrology and material science.

Origin. From Latin absorbere, to take away; related terms include absorbance in spectroscopy and absorptivity of materials.