a ball bearing is a type of rolling-element bearing which uses balls to maintain the separation between the moving parts of the bearing.

Ball Bearing

a ball bearing is a type of rolling-element bearing which uses balls to maintain the separation between…

A pair of hands forming a long section of rolled clay into a container.

Modeling a clay container

A pair of hands forming a long section of rolled clay into a container.

A pair of hands smoothing a clay container formed by curling large sections of rolled clay together.

Smoothing a clay container

A pair of hands smoothing a clay container formed by curling large sections of rolled clay together.

"In geometry, a curve generated by the motion of a point on the circumference of a circle which rolls upon the convex side of a fixed circle." -Whitney, 1911

Epicycloid

"In geometry, a curve generated by the motion of a point on the circumference of a circle which rolls…

A pair of hands rolling clay into a cylindrical shape.

hands molding clay

A pair of hands rolling clay into a cylindrical shape.

An illustration of a group of men rolling barrels of flour down a steep enbankment

Men rolling Barrels

An illustration of a group of men rolling barrels of flour down a steep enbankment

A roller. Crushes clods and packs the surface so as to keep the seed moist at the expense of increased evaporation.

Roller

A roller. Crushes clods and packs the surface so as to keep the seed moist at the expense of increased…

Spiral with lines AB and CD drawn on piece of paper and rolled into a cylinder to form spiral running from A to D.

Spiral Drawn on Piece of Paper and Rolled

Spiral with lines AB and CD drawn on piece of paper and rolled into a cylinder to form spiral running…

A cylinder of wood, plastic, cardboard, or other material on which wire, thread, or string is wound.

Rack Spool

A cylinder of wood, plastic, cardboard, or other material on which wire, thread, or string is wound.

"Reading a Volumen, or Roll." — Quackenbos, 1882

Volumen

"Reading a Volumen, or Roll." — Quackenbos, 1882