The aeolipile is a reaction machine that can be considered the precursor of the modern jet propulsion motor.

Heron of Alexandria, the famous engineer inventor, described this apparatus in 120 BC, thus anticipating James Watt. It consists of a hollow metal sphere with two small inclined tubes from which steam is expelled. To use it, water is introduced with a syringe into the sphere and the apparatus is warmed up until the water boils. Then the steam that is given off produces a fast revolving movement due to the pressure of the steam on the back of the tube facing the exit holes.

 

Hand-made piece. Materials: brass and walnut wood. Dimensions: h=29cm. Design: Marc Boada, 1993 (from various sources).

All bodies can display three types of balance: indifferent, unstable and stable. The object shown here is a classic demonstration of stable balance. This is because its center of gravity is always below the point at which it is supported, thanks to the two counterbalances at the ends of the rods.

This is a faithful reproduction of the Ivory Tightrope Artist of the Cabinet of the famous physicist Caesar-Alexandre Charles (1746-1823), which is held today in the Musees des Arts et Metiers in Paris.

 

 

Hand-made piece. Materials: copper, polyurethane, brass and resin. Dimensions: h=28cm

Place the double cone of this model in the lower part of the rail. If it rolls, what's happening? Common sense tells us that it won't move, because "it would climb" the rails. However, against all reason the double cone "rolls upwards".

Is it possible that if we let an object free it will "fall upwards"? We have many experiences in life that indicate to us that this is absurd. If we let loose an object from a certain height it will always falls towards the ground and never rise above its starting point. Moreover, these experiences have been grounded in physics ever since Newton stated his well-known Law of Universal Gravitation, and we know that the Earth attracts masses towards itself with a force we called weight.

In fact, the double cone does not really ascend. Like all objects it rolls downwards. Although the impression produced is that it rolls upwards, what happens is that, because of the geometry of the piece, its center of gravity is descending, like any other object that is dropped. For this reason we call this experience a paradox: an apparent violation of the Law of Universal Gravitation takes place but more a detailed examination of what in fact happens quickly corrects this impression.

Hand-made piece. Materials: gold leaf, wood, brass. Dimensions: h=12cm.

All rotating bodies have two qualities: one is rotational inertia and the other directional inertia, that is to say, the angular moment. All the peculiar movements of the gyroscope are produced by this effect.

The gyroscope was invented by Leon Foucault in 1852 and he used it to demonstrate the rotation of the Earth. Today they are used for, among other things, boat stabilizers or in airplanes' automatic pilots

 

 

Hand-made piece. Materials: aluminum, brass, bubinga wood. Dimensions: High Gyroscope h=25cm, Gyroscope h=10cm. Design: Marc Boada, 1992.

It is one of the scarce examples that allow to view the mechanical work that produces a potential difference chemical without chemical reaction being produced one.

The bird consists of two spheres of crystal connected by a tube of the same material that is introduced in the inferior sphere. In the interior of the bird there is not air, it only contains a highly volatile liquid, normally chloride of methylene (CH2Cl2), with a boiling point near to the ambient temperature. This internal liquid is in thermal equilibrium with its steam.

The peak of the bird is covered of a porous material that once is introduced in the contained water in the glass, makes the bird never leave of drinking of her. Which phenomenon originates this movement of oscillation?

?Ref. J. Güémez, R. Brave, C. Fiolhais, and M. Fiolhais, 'Experiments with to sunbird,'' Am. J. Phys. 71, 1257-1263 (2003).

The light is energy and in this device called radiometer, invented by William Crookes (1832-1919), it transforms into mechanical movement. The radiometer of Crookes consists of four light sheets blackened on a side and silver-plated by the other one and placed in a common pivot so they can turn freely. Pressure of approximately 10 mm of mercury up to one is evacuated by the glass package that contains them. At this pressure there are still many molecules of gas that interact with the plaques. When a light source to the radiometer comes close, the crosses start to turn and in the end make it at quite a lot of speed.

To justify this movement there are two possible explanations: (1) most of the photons are absorbed by the side blackened of every plaque, but the majority is reflected by the reflecting side, transferring like this more quantity of reflecting movement nearby, causing the rotation in the address of the black side. (2) la majority of the photons is absorbed for the black side, but the majority is not absorbed by the reflecting side, warming up like this the black side more than the reflecting side. The molecules of air make contact with the plaques obtaining more energy of the black sides, being startling with bigger transfer of moment of that side, causing like this the rotation in a meaning such that the black side moves back of the fountain. This is the correct result.

If we do to rotate an object, a magnitude is a priori little evident that it is the moment of inertia. The moment of inertia is a vector perpendicular to the rotation axis, which in the case of a cylinder is equivalent in half of its mass for the square of its radius.

As every vectorial magnitude, this has trend to maintain constant in module, meaning and address unless we apply a force that alters it, as for example, the friction, but also a change in the angle of position of the object. Thus, we see that if we try to incline a steering wheel in rotation, this offers endurance.
A drum is not more than a thin cylinder that pivots on a perfectly vertical axis and perpendicular to the plan of rotation, and well lubricated with the end to prevent the leak to the utmost for the moment of inertia for friction. Thus, this way, giving a sufficient impulse, the steering wheel keeps in rotation during a long while.
This estate is used in cyclic machines, as for example, in the explosion engine of a car for reduce the speed variations when there are changes in the driving torque or the couple of burden inside the cycle. They still have another more recreational estate and is that of accumulating inertia in those small cars of toy that he "load" rubbing the wheels against the ground.

Hand-made piece.
Materials: copper and brass.
Dimensions: h=17cm.

Seven equal steel balls hang perfectly in line, touching each other. What happen if we crash a ball on the end into the others while the are at rest? What if we dropped two balls?
Through this device, the law of conservation of energy is demonstrated. The dropped ball strikes to the second ball, which then tranfers kinetic energy to the third, and so on down the line. The last ball cannot transfer the energy, therefore it moves in similar form to the crashing ball. When returning to the position it returns to initiate the process of energy transmission until the opposite end (to the first ball).

Hand-made piece.
Materials: aluminum, brass, bubinga wood.
Dimensions: h = 18 cm
Design: Isaac Newton.

August Ferdinand Möbius (1790-1868) was born in Schulpforta, Germany. He was pupil of Gauss and exerted as astronomer and mathematician in the University of Leipzig. He was one of the pioneers of the topology, area in which it investigated the surfaces of a single face, as its famous ribbon, discovered in 1858.
The ribbon of Moebius is a surface as simple as surprising. If we catch a ribbon of vertices ABCD and we join we, A, with D and C with B turning around it obtain a surface that against every appearance has a single face, a single edge and is not adjustable. If we set off from a point of its surface and start to color it, we will finish all the ribbon painted without having gone beyond the edge. Therefore, it only has a face. If we outline one of the edges with the finger we arrive to the preliminary point having gone over the two visible edges. And the most surprising thing: if we consider a vector n perpendicular to the plan of the ribbon in any point p, this will change its direction as we go over the ribbon for its central line, getting to convert in -n when arriving to the same point.
The ribbon has other possibilities of experimentation. If we cut it once throughout its midde line, we obtain a single ribbon with four half returned, that if that it has two faces. If we cut it again we obtain two intertwined ribbons that are not either of Moebius.
The ribbon of Mobius has practical applications. We can obtain a conveyor belt of uniform wear for "both faces", and therefore with more durability, or else a more efficient abrasive ribbon.

Hand-made piece
Materials: copper, brass and wood
Dimensions: h=26 cm

When initiating the civil war in Spain, in 1936, a Catalan republican youngster had to emigrate to France where he was received in a field of refugees. With the aim of having a better deal it decides to note itself as mechanic in the factory, without his having ever been. There it discovers a new world of precisión. La ribbon of Mobius has practical applications. We can obtain a conveyor belt of uniform wear for "both faces", and therefore with more durability, or else a more efficient abrasive ribbon.

It finishes the war and little to little the refugees go back home, and he returns with an object of memory: a marvelous center finder of stainless steel, very strange and also very expensive material for then.

The part arrived at the hands of its grandson Jaume Aguado, excellent turner, who incorporated her to the factory of Pèndulum, where we use it|her to journal to find the center of the cylinders with every easiness. Now we have decided to do the retort that you have in your hands and which we expect to accompany you a lot of time.

Part prepared by hand.
Materials: copper, brass and wood.
Dimensions: h=26 cm

The enigmatic helix behaves in an unusual way: it has the extraordinary particularity of turning in only one direction.

Try this: push one end in a counter-clockwise direction and ... what happens? Although the helix makes one or two turns, it ends up wobbling and then turning in the opposite direction. Repeat the experiment but in a clockwise direction, and it turns normally until the initial impulse is finished.

How to explain this unusual behavior? Look closely at the object: although it is elliptical, the surface on which it turns is slightly helicoidal, similar to the propeller of an airplane. This generates a difference in the distribution of the mass of the object that, combined with its asymmetrical shape with respect to the direction of rotation, produces a different effect when it turns in one direction or the other. A more sophisticated explanation of this effect is very complex and there is not even a single theory to explain it.

This helix is an exact replica made from a mould of one which circulated among the physicists who worked in the particle accelerator of the CERN project in Geneva during 1980s. The original was of lead and become easily deformed. This one has been perfected by making it of pewter (an alloy of zinc, tin and lead, much harder than just lead).

The base is of agate, a very hard stone that facilitates the rotation of the helix with minimal friction.

A flat surface with one end raised to certain height forms what is known as an inclined plane or ramp. This simple machine allows objects to be raised or lowered by sliding them up or down, reducing the effort required to raise an object in a vertical direction. As the slope of the inclined plane is reduced, so it becomes easier to move the object along it.

This is the reason why roads in mountainous areas are made of curves that have a limited inclination, so that the ascent can be made without forcing the motors of the vehicles too much, or the muscles of our legs.

Hand-made piece.
Materials: beech wood, walnut and brass.
Dimensions: h=30.5cm.

The operation of the pulley is based on the lever and allows us to change the direction of a force. If the pulley is simple, the force needed to raise a weight is equal to that weight. If, on the other hand, a system of pulleys is being employed, the force that needed is much smaller.

Archimedes managed to move a boat loaded with passengers and goods by means of a system of pulleys, at the request of King Hieron of Syracuse.

Hand-made piece.
Materials: beech wood, walnut and brass.
Dimensions: h=32.5cm

The winch consists of a cylinder perpendicular to a wheel. A rope coiled round the axis of the cylinder and the weight that has to be raised is attached to it. The force necessary to lift the weight is exerted on the wheel. This force causes the cord to coil round the cylinder and the weight to rise.

The winch is an application of the lever that allows the force to be amplified.

Hand-made piece.
Materials: beech wood, walnut and brass.
Dimensions: h=36cm

This machine is nothing more than a wedge that is introduced by one of its edges between two obstacles, in order to produce two lateral efforts that tend to separate them. This effort will be divided in two parts, one perpendicular - to which all the useful effect will be due - and another parallel - that will only serve to make the hammer slip.

This explains how and why axes have quite a sharp cut.

Hand-made piece.
Materials: beech wood, walnut and brass.
Dimensions: h = 31.5cm