Concrete, steel, wood, rebar and science: this Discovery Channel program looks at the physics, biology, geology, mathematics, aerodynamics, chemistry, hydrodynamics, electrical engineering, thermodynamics and psychology involved in home construction.  4;Concrete and Steel" (21 minutes) surveys how houses are built; "Wood Works" (28 min.) shows how a tree becomes a wall. Hosted by Steve Hanneman. Closed captioned.