c.1300, impose a tax on, from Old French taxer impose a tax (13c.), from Latin taxare evaluate, estimate, assess, handle, also censure, charge, probably a frequentative form of tangere to touch (see tangent). Sense of burden, put a strain on first recorded 1670s; that of censure, reprove is from 1560s.
The average depth of frost penetration ranges from 25 inches (64 cm) in southwestern South Dakota to 50 inches (127 cm) in. the northeast. Depth of frost depends on the amount of residue cover, soil moisture content, and the amount and timing of. snowfalls in relation to temperature extremes.
Students will measure the depth of freezing as the ground cools.  Depth of Freezing = distance in the Frost Tube (inner tube) from the soil surface to the boundary between the ice layer and unfrozen water. This represents the depth of freezing between the soil surface and the underlying unfrozen soil.