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| The Columbus Ships and Power of Simple Machines.** |
| Columbus and his crew would not have accomplished the voyage from Spain to the Bahamas if not for the power of simple machines. They were a vital component that allowed the sailors to keep the ship in good condition and running smoothly. Simple mechanical systems such as levers and pulleys, wheels and axles and inclined planes helped to lessen the manpower needed to accomplish heavy shipboard tasks such as raising anchors, raising sails, pumping bilges, and loading cargo. |
The Capstan-Workhorse of the Columbus Crew
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| Definitions and Terms for Simple Machines: |
Machine: a device that makes work easier.
Simple Machine: a device that works with only one movement.
Compound machine: a combination of two or more simple machines
Lever: a bar that pivots or turns about a fixed point
Fulcrum: the fixed point of a lever
Wheel and axle: A lever that rotates around a center point or fulcrum. Wheels of different sizes that rotate together such as a gear are a type of wheel and axle.
Inclined plane: a gradually sloping surface, such as a ramp, that is used to raise objects.
Wedge: an inclined plane with one or two sloping sides such as used in splitting logs.
Screw: an inclined plane that is wrapped around a cylindrical center post.
Effort Force: the force applied to the machine.
Resistance Force: the force which is applied by a machine to overcome resistance of gravity or friction.
Mechanical Advantage: the number of times a machine multiplies the effort force.
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| Simple and Compound Machines used aboard Columbus’ Ships |
Capstan-a compound machine
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Capstan-an apparatus enabling the anchor to be raised by hand. It is an upright cylindrical barrel revolving on a spindle. It consists of a lever which uses a drumhead with bars and a wheel and axle at the bottom with gears. This compound machine was used until the end of the sailing era (around the turn of the 20th Century). |
| Block and Tackle-A grooved pulley with a rope or chain running along the groove. Pulleys are mostly used to lift objects. A fixed pulley changes the direction of the force which is applied to the end of a rope. A pulley is a cylindrical lever. Blocks and tackles could be arranged to multiply force to “raise a purchase” or large load such as an anchor or cargo or sails. |
A fixed pulley
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The tiller is a lever
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Tiller and Rudder-A tiller or till is a long pole or handle attached to a rudder. The tiller is a lever which provides leverage for the helmsman to turn the rudder which steers the ship. The tiller can be pushed or pulled directly or by use of a system of pulleys. When the tiller is moved in one direction, the bow or front of the ship will turn in the opposite direction. |
| Ramp-a ramp is an inclined plane. An inclined plane allows large loads to be moved up ramps with a smaller effort force than would be required to lift the load. The longer the inclined plane, the easier the effort force. Loading ramps on ships are inclined planes. |
A loading ramp is an inclined plane
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Bilge Pump with T handle
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Bilge Pump—a bilge pump consisted of a long hollowed out log that extended down to the bottom of the ship with a plunger that had either a T or a Lever handle attached at one end and a metal “rose” and leather flange at the other. By pumping the handle up and down, suction and gravity raised the water up the column and out on deck. The pump with the lever handle also employed a lever system to pass energy to the handle. |
**Science concepts. The student knows that there is a relationship between force and motion.
The student is expected to demonstrate basic relationships between force and motion using simple machines including pulleys.
**Science concepts. The student knows concepts of force and motion evident in everyday life.
The student is expected to calculate speed, momentum, acceleration, work, and power in systems such as in the human body, moving toys, and machines.
The student is expected to investigate and demonstrate mechanical advantage and efficiency of various machines such as levers, motors, wheels and axles, pulleys, and ramps. |
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