EAS 201: Lecture 13
February 4, 2019
• Notes referring to Karlis Muehlenbachs’ slides, February 4, 2019.
• pH as a measure of how much hydrogen ions are present (hydrogen ions produced by
dissociation of water).
o If H+ concentration goes up, water becomes acidic.
o If it goes down, water becomes alkaline.
o Rain water has pH ~ 5.6.
o Pure water has a density maximum at 4 degrees Celsius.
o Salty water – higher salinity means higher density.
• Properties of Ice:
o Is an unusual mineral.
o Has an open crystal lattice – has lower density than liquid.
o It floats, water expands as it freezes → expanding freezing water can fracture
• Phases of Water:
o Solid, liquid, gas.
o Energy Absorbed: (gain) solid → liquid → gas
o Energy Released: (loss) gas → liquid → solid
• Hydrosphere – all water at or near the surface
of the Earth.
o Surface of the Earth is 3/4s water.
o Image from Karlis Muehlenbachs’ lecture
o Oceans = 97.5% Earth’s water.
o Glacial Ice = 1.81% Earth’s water.
o Ground Water = 0.63%.
• Water moves downhill during rainfall.
o Initially as sheet flow (overland flow).
o Is concentrated into stream flow.
▪ Consists of storm flow & base
▪ No base flow = ephemeral.
▪ Base flow = perennial.
• Body of flowing water confined to a channel is defined as a
o River is used to describe major branches of a stream
o Area where stream draws its water supply from is the