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Perpetual Motion Machine

The classic overbalanced wheel, AKA "perpetual motion machine", as designed by French Architect Villiard De Honnecourt in about 1235, and studied extensively by Leonardo Da Vinci in the late 1400's.

The overbalanced wheel is the oldest attempt at a perpetual motion device in history. The oldest known description of one is from 8th century India - a wheel with vials of mercury arranged in such a way that as the wheel rotates, the mercury sloshes away from the center on one side, but towards it on the other. However, mercury is expensive, very heavy and (we now know) dangerous. In later years, the mercury was replaced with shifting mallets, but the operating principle is the same.

The oldest surviving drawing of a perpetual motion machine was made by the French architect Villiard De Honnecourt in about 1235. He wrote:
Many a time have skillful workmen tried to contrive a wheel that should turn of itself; here is a way to make such a one, by means of an uneven number of mallets.
-- Villiard De Honnecourt, 1235 AD
Leonardo DaVinci studied the concept in depth, and he also constructed several models - the models have not survived the ages, but dozens of his drawings have survived. Ultimately, he concluded that perpetual motion was indeed, impossible, and he abandoned the idea completely.

This particular model is a kit. When assembled, it is an historically accurate representation of the concept, complete with a crank-arm for "starting" it. We consider it to be a kinetic sculpture, inspired by the work and the genius of the ancients. It makes a fabulous conversation piece, and when treated with a finishing wax or hand-rubbed with fine oils, is suitable for prominent display in any museum or display case.

The kit is manufactured from 100% solid hardwood. The finished model is 22 inches tall, 6 inches wide and 18 inches long. All parts are computer manufactured for guaranteed fit and accuracy. Everything you need to construct this kit is included except for a few simple tools. All you need to supply are scissors, a utility knife, sandpaper (to smooth any rough edges), some wood glue, a ruler and some rubber bands (or small clamps) to hold parts together while the glue dries. It takes about three to six hours to assemble, depending on how much attention to detail you put into it.

It's a fascinating piece of engineering history. A concept more than a thousand years old, that failed in its design goal, yet still manages to capture the imaginations of people generation after generation.

PLEASE NOTE: We've had far too many people buy this item and later complain that it doesn't work. In case our educational system has failed you too, please let me explain - Perpetual motion is impossible. This truth has been proven by science many times over, and has been known at least since the time of Leonardo DaVinci. It's a fantasy that didn't work in ancient times, and it doesn't work now. We're not trying to trick you. This kit is a reproduction of the concept, intended for display. It is meant for people who enjoy building models and have an interest in mechanical art, the history of engineering and physics, and/or teachers who need something to prove to arrogant students that this idea just won't work! It is, however, a beautiful and fascinating mechanical device. We actually keep one on display in our living room.

Tools required:
Scissors, Glue, Ruler, and a utility knife. Sandpaper is optional.

Assembly time:
For a Master carpenter doing a sloppy job: about three hours.
A person with no kit building experience being extremely meticulous: about a week.
The model in these photos was built by Ron Toms in about four hours.

Assembled Size:
- Height: 22"
- Width: 18"
- Depth: 6"

Shipping weight: 5 lbs.
Box dimensions: 12" x 24" x 4"

Quantity pricing info:
0 to 4 kits, standard price.
5 to 9 kits, 10% off
10 or more kits, 15% off

Orders of $200 or more get FREE ground shipping!

For more discount pricing info, please visit

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    Price: $169.00
    Minimum age: 8
    Availability: out of stock

    Item code: 14100

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Villiard de Honnecourt's original drawing, circa 1235 AD.

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How it's supposed to work:

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On one side of the wheel the hammers extend straight out, making a longer lever arm (the distance from the center of the wheel to the hammer's head). On the opposite side of the wheel, the hammers lay close and make a short lever arm. Since the lever ratio is greater where the hammers stick out, it's unbalanced and makes the system want to tip, and thus the wheel to rotate. As it rotates around, the next hammer falls into place continuing the motion "perpetually". Of course, we now know that such a device will never actually work, but the subtle reasons why it won't work can be elusive.

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Kids love it!

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