01:14
The Water Planet: Origin of the Solar System
Several billion years following the "Big Bang," a cloud of dust and gas began to condense and rotate, taking on a spherical shape. Eventually, the
Subject: dust
Transcript: . eventually, after several billion more years had passed, Ma cloud of dust and gas begins to condense and rotate, taking on a spherical shape. [roundy:] now in
05:51
Occupational Safety and Health: Worker Safety in the Mining Industry
of dust created by the continuous mining machines. Today, operators work in pressurized cabs sealed against dust and provided with a clean air supply.
Subject: dust
Transcript: . We increased the levels of dust... That existed in the mines. That led to this epidemic of black lung disease In this country. The pneumoconiosis, or