Soils Exam 2

Weakest forms of bonding

Hydrogen bonds.

As water gets colder

It gets denser.

Coheasion

water molecules attracted to each other

Adhesion

water molecules attracted to solid surfaces

Surface tension

Cohesion between water molecules allows for resistance against an applied force. It can help give structure to soils.

Unsaturated zone

zone of soil, sediment or rock above the water table in which pore spaces are partially or completely filled with air.

Saturated zone

Rock openings are filled with water.

Soil water potential (Ψ) [kPa]

Energy state of the soil water relative to pure water.

Soil water content (Θ)

How much water is associated with a given volume of soil.

Percent saturation (S)

Vwater/Vpores

Θv

n*S

Gravitational potential (Ψg)

water density*gravity*height of soil from reference elevation.

Pressure potential (Ψm and Ψh)

m is matric potential (unsaturated) and h is hydrostatic potential (saturated)

Matric potential (Ψm)

negative pressure or tension.

Osmotic potential (Ψo)

Decreases with increasing solute content.