Whirling Tables and Accessories
| The Whirling Table Apparatus has a history
dating back at least to 1713. It is shown in A Course of Mechanical, Optical,
Hydrostatical and Pneumatical Experiments, To be perform'd by Francis Hauksbee;
and the Explanitory Lectures read by William Whiston, published in London
In the experiment at the right, a body G in
a tilted glass tube has the necessary centripetal force supplied by a string
passing down the center of the whirling table with a weight suspended from
|| This rotator, in use in lecture demonstrations at
Kenyon College, is by James W. Queen of Philadelphia, and is listed,
fully equipped at $40.00 in the 1888 catalogue. The catalogue copy
shows the Figure
of the Earth apparatus.
| In this whirling table attachment, a large and
a small ball are connected by a tube sliding on a smooth rod. If the center
of mass is coincident with the whirling axis, the balls have no radial motion.
But, if the center of mass is moved to the side by sliding the unit in either
direction, centripetal force will cause the unit to slide to one end when
the system is whirled about a vertical axis. This apparatus is at Colby College.
|| This whirling table attachment, in the collection of St.
Marys College in Notre Dame, Indiana, shows the action of bodies of various
densities in a rotating frame of reference. The glass tubes are filled part
way with water; on one side is a small amount of mercury, and on the other
side is a cork. When the system is spun about its axis of symmetry, the more
dense object flies outward: on one side the mercury rises through the water
and goes to the upper end of the tube, and on the other side the water is
on top and the cork is on the bottom.
| This is the only piece of apparatus I have seen
thus far by Millington of Philadelphia. It is in the collection of Colby
College in Waterville, Maine, and is used to study centripetal force. Cords
connect the two sliding masses with the platform in the middle, on which
weights may be placed. These weights supply the centripetal force needed
to maintain the weights spinning at a constant radius.
This is the same experiment shown on the whirling table
from Hauksbee and Whiston at the top of the page.
|| Troughton and Simms of London made this double whirling
table, with each side equipped with apparatus similar to the picture above
to study centripetal forces. This apparatus was made after 1832, when Troughton
became Troughton and Simms, and was donated by the University of Alabama to
the Smithsonian Institution. This is a Smithsonian photograph.
The device below is at Case Western Reserve University in Cleveland, Ohio.
The centripetal force to keep the sphere at a constant radius is supplied
by a calibrated spring in the interior of the long, hollow tube on the left.
These two centripital force devices are in the collection of
Case Western Reserve University in Cleveland, Ohio.
They are placed in a rotator and spun. The necessary centripetal force to
keep the horizontally-sliding masses in place is
|supplied by the large brass weight, which is free
to slide up and down and is attached to the rotating masses by strings. The
upper device is by Gaertner of Chicago, while the lower one is unmarked.