1. Soil Physics 2010 Outline Announcements Soil Thermal Regime Ice (courtesy of Yuki & Ranae)

2. Soil Physics 2010 Announcements Homework 6 due Friday (I recommend the linear/Moldrup relationship in #3) No more typos? Eric’s presentation posted Review sessions next week (fake) Quiz!

3. Soil Physics 2010 Quiz, question 1: A 2 nd -order partial differential equation has appeared in various forms in recent lectures. Only a few variables, and the proportionality coefficient, differ from one form to another. Write one form of this equation as we have used it. Hydraulic diffusion Molecular diffusion Thermal diffusion (heat flow)

4. Soil Physics 2010 Quiz, question 2: Gradient of What? What Moves? Name of the Proportionality Coefficient What is Conserved (Transient Form)? Darcy ’ s Law Fick ’ s Law Fourier ’ s Law Extra credit: Ohm ’ s Law

5. Soil Physics 2010 Quiz, question 2: Gradient of What? What Moves? Name of the Proportionality Coefficient What is Conserved (Transient Form)? Darcy ’ s Law Water Potential Fick ’ s Law Concen- tration Fourier ’ s Law Tempera- ture Extra credit: Ohm ’ s Law Electrical Potential

6. Soil Physics 2010 Quiz, question 2: Gradient of What? What Moves? Name of the Proportionality Coefficient What is Conserved (Transient Form)? Darcy ’ s Law Water Potential Water Fick ’ s Law Concen- tration Molecules Fourier ’ s Law Tempera- ture Heat Extra credit: Ohm ’ s Law Electrical Potential Current (electrons)

7. Soil Physics 2010 Quiz, question 2: Gradient of What? What Moves? Name of the Proportionality Coefficient What is Conserved (Transient Form)? Darcy ’ s Law Water Potential Water Hydraulic Conductivity (or diffusivity) Fick ’ s Law Concen- tration Molecules Molecular Diffusivity Fourier ’ s Law Tempera- ture Heat Thermal Diffusivity Extra credit: Ohm ’ s Law Electrical Potential Current (electrons) Electrical Conductivity

8. Soil Physics 2010 Quiz, question 2: Gradient of What? What Moves? Name of the Proportionality Coefficient What is Conserved (Transient Form)? Darcy ’ s Law Water Potential Water Hydraulic Conductivity Water (volume) Fick ’ s Law Concen- tration Molecules Molecular Diffusivity Mass (molecules) Fourier ’ s Law Tempera- ture Heat Thermal Diffusivity Energy (heat) Extra credit: Ohm ’ s Law Electrical Potential Current (electrons) Electrical Conductivity Charge (electrons)

9. Soil Physics 2010 Summary Gradient of What? What Moves? Name of the Proportionality Coefficient What is Conserved (Transient Form)? Darcy ’ s Law Water Potential Water Hydraulic Conductivity Water (volume) Fick ’ s Law Concen- tration Molecules Molecular Diffusivity Mass (molecules) Fourier ’ s Law Tempera- ture Heat Thermal Diffusivity Energy (heat) Ohm ’ s Law Electrical Potential Current (electrons) Electrical Conductivity Charge (electrons) The stuff that moves is conserved The gradient is about how “strong” or “active” that stuff is

10. Soil Physics 2010 Soil thermal regime Steady-state Transient Instantaneous change (like infiltration) Cyclical change New! Improved! Dynamic! (Like Darcy’s Law) This is how we usually study soil thermal regimes.

11. Soil Physics 2010 A particular part of the soil thermal regime: Ice by Yuki & Ranae