The optical disks, the inertia spheres and the pentaphone of Aristotle's Park in Chalkidiki.

…Άπαν το κινούμενον υπό τινος ανάγκη κινείσθαι… (everything moving is needed to be moved by something)

Another great place you should definitely visit is the Park of Aristotle in Stagira, at this mountain village of Chalkidiki. Aristotle might have been born in Ancient Stagira near Olympiada, but the place he is now living is this amazing theme park inside the mountains, where his natural laws are practically presented through experimental instruments placed all over the park.

From the entrance i could see the imposing statue of Aristotle, made by sculptor Nicholas, and when i looked it from underneath i could see the figure joining the dense clouds, placing the statue to a different visual dimension. A little further you will find yourself on a balcony overlooking the Gulf of Ierissos where you can grab the binoculars to gaze at the details of the landscape. But enough with all that, let's talk about the fun part of the park - the instruments!

• Compass: It is placed in front of the statue of Aristotle and symbolizes that his philosophy has reached every part of the world, and is a starting point of modern worldwide scientific thought, and belongs to humanity. It displays the direction and distance of the most famous cities in the world, in relation to the park.
• Prism: The white sunlight passes through the special prism and the famous “colors of the rainbow” are analyzed due to the different speeds of each individual radiation, since each different wavelengthed radiation exits through a different angle.
• Sun clock: The large, horizontal sun clock shows the exact time of the place you are. There is a difference of 1 hour and 25 minutes to the current time during summer and 25 minutes difference during winter. The curved lines on the plate of the clock are for the identification of the current month.
• Lens: The sign next to the lens informs us that every photon, i.e. every minimum amount of light, has little energy by itself, but when every one is concentrated in one spot then that energy becomes greater.
• Pentaphone: It consists of five large pieces of granite that have been calculated to produce a sound of different frequency, a different note. These five notes sound according to the pentaphone ancient scale.
• Optical discs: Experimenting with the optical discs, you will find that when the images pass in front of our visual field with great speed, the human eye does not understand them as different, but it creates a continuous visual whole as if we are watching a movie. This happens because the impression of the image lasts for 1/16 of a second on the optical nerve due to inertia. This quality of the eye is called persistence of vision. Cinema actually depends on the “inability” of the eye to see more than 24 images per second.
• Pendulum: Older people will remember and younger will learn that the energy of one of the systems that initiates the oscillation is transferred to the other due to conjunction. The effect is that the oscillation width is reducing into the first system, while it is increasing into the next.
• Water turbine: By rotating the lever we can create a swirl in the liquid that is contained in the transparent container, and understand the physics of the phenomenon, or compare it with the rotation of the wind that creates a tornado.
• Inertia spheres: By playing with the inertia spheres, we are always impressed by the phenomenon of transfer of momentum, when during the first impact, the initial momentum is maintained and is consecutively transferred from the first sphere to the last.
• Parabolic reflectors: They are placed in a straight line with a large distance from each other. If two people stand in front of each one, they can have a conversation even if they whisper. This happens because the transferred through air sound waves, are reflected, their energy is concentrated in the center and the sound ends up amplified in the ears of those participating in the experiment.

Source Aristotle Municipality