“Understanding by doing” is the philosophy Cesare Baj has always applied as part of his commitment to promote the diffusion
of scientific knowledge.
The author
Cesare Baj is the son of an engineer and philosopher, who has been passionate about science and technology since childhood. He has always had a particular instinct for forms of popularization and teaching that combined the transmission of knowledge to activities to be carried out.
He has consistently applied this principle in the various publishing branches he has worked in, putting it into practice with the design and production of numerous kits targeted at science and technology enthusiasts, including dozens of gadgets proposed in conjunction with culturally focused editorial products.
He has also carried out consultancy work and led experimental activities in Montessori schools.
He co-organised the “Paper tools to teach science” workshop with the famous designer Bruno Munari.
Indeed, the philosophy “Understanding by doing” can be magnanimously applied to any field, as demonstrated by his recent works in the area of mathematics, which has been wrongly judged as being an “abstract”, “arid” and “difficult” matter.
An overview of his main works, produced in-house or for other publishers over the past decades are listed below.
Kits and gadgets designed and produced by Cesare Baj
The Complete Game of Astronomy
1980
A set of classical instruments, made out of cardboard, used by astronomers and topographers dating from the Renaissance period to observe the night sky and conduct experiments.
Italian and French editions were produced.
The same and other similar materials were included in a 6-volumes encyclopedia of astronomy.
An abridged German edition was also released .
Astrolabe
1980
An astrolabe covering 8 latitudes. The first ever instrument able to show in addition to stars the position of the True Sun, represented by a lemniscate in the form of a figure of eight visible on the transparent cursor.
Italian and French editions were produced.
Newton, a monthly magazine focused on “science, technology and fantasy” edited by Cesare Baj
1981-1982
The first European science magazine published for young adults containing cut-out materials in every issue to carry out experiments.
Orientation, Topography, Navigation
1985
A set of 33 instruments used by navigators, topographers and those involved in the sport of orienteering.
Italian and French editions were produced as well as an abridged German edition.
Advanced pilot computing and plotting kit
1986
A set of instruments intended for aeroplane pilots.
The ‘Espresso’ magazine sundial
1986
‘L’Espresso’ is a popular Italian magazine (approximate circulation of 600,000 copies). One edition featured a free portable sundial.
Hoepli Pocket Planetarium
1987
A special version of astrolabe that was produced for the ‘Hoepli’ publishing house in Milan specializing in scientific literature.
It’s a universal astrolabe, i.e. usable at all latitudes, based on a projection studied by Juan de Rojas in the 16th century.
The wearable sundial
1992
An amusing T-shirt able to tell the time.
It comes complete with a compass and instruction manual.
Cosmombrello
1986
A high-quality, dual purpose umbrella that can also be used as a portable planetarium.
It’s accompanied by an instruction manual.
Birdsong
Animal sounds
1993
A range of audio cassettes produced as a simplified young adult edition of a more comprehensive product originally targeted at adults.
Other audio products:
- Introduction to radio listening using HF frequencies
- Audio guide to the night sky
- “Impossible interviews” with prominent historical scientists
- Radio communications extracted from aircraft accidents and their analysis
Gadgets for editorial products
Since the 1980s
Cesare Baj has produced over 100 cardboard gadgets for newspapers and magazines that have been distributed by the most important Italian publishers.
These include tailormade slide rules designed to solve specific problems, as well as additional items designed to present data in a simple and appealing way.
The most curious gadget was a “Govern-o-meter”, attached to a weekly magazine in anticipation of the elections. This tool allowed readers to simulate the formation of the new government based on election results (it functioned in the proportional election system in force in Italy at the time).
Circulation numbers: from a few thousand to more than half a million pieces.
Pop-up maps
Year 2000 onwards
The Map Architettura a Como 1920-1940 shows the location of the buildings constructed between 1920 and 1940 in the city of Como by the architects of the “Como Rationalism” modernist movement, who left an important legacy of works that are now used as classic references of modern architecture.
On the back of the map, the pictures of the buildings.
Scientific toys
Cesare Baj participated in the design of a series of plastic scientific toys produced by Navir – Milan.
He also prepared the instructions in four languages attached to the toys, describing the experiments that can be made.
Super Optic Wonder
Inseparable companion for the excursions and adventure, its functions are: binoculars, magnifying glass, compass, magnifying mirror, stereoscopic viewer, heliograph, electric torch, whistle, morse code, universal sundial, quadrant.
Microscope
Portable microscope with illuminating torch; zoom from 20 to 40 magnification. Focus is obtained by rotating the microscope house on the underlying funnel. Zoom variation is obtained by means of the small wheel inserted in the object.
Gyroscope
Books on water aviation
1991-2025
Cesare Baj, a seaplane pilot and instructor, is the author of several books on water aviation.
The principal work is the >500-pages Seaplane Operation – Basic and advanced techniques for floatplanes, amphibians and flying boats from around the world, with editions also in French and Italian (one in Turkish is in progress).
Another book is on how to fly Lake amphibians, a family of light flying boats.
In volo sull’acqua is a book of memoirs about three decades of water flying by the author, published in 2004.
Baj is presently the Honorary President of Aero Club Como – Como, Italy, the oldest seaplane operation in the world, managing a flight school, a commercial transportation company with seaplanes, a documentation centre on water flying and the International Como Water Aerodrome.
Seaplane Operations includes a special slide rule designed for solving specific problems while flying a seaplane.
Seaplane Operations introduces pilots and readers alike
to the world of water aviation.
Technical explanations in the book are brought to life
by an unparalleled illustrative compendium
that is enriched by the author’s real life anecdotes
and contributions from the most experienced
seaplane pilots of past and recent eras.
Sundials
1995
A complete sundial construction kit produced for the ‘Hoepli’ publishing house in Milan specializing in scientific literature.
It includes specific plastic instruments, 30 cardboard computing instruments and demonstration-sundials.
An instruction manual teaches how to construct various types of sundials.
A few sundials designed by Cesare Baj
Polar sundial with zodiacal calendar
This sundial is given in the form of a sheet of cardboard, from which pieces are cut and assembled.
The sundial is a zodiacal calendar, but not as it is intended by astrologers. The instrument is designed to indicate the presence of the Sun in the real constellations of the zodiac. Among them, the 13th zodiacal constellation, Ophiucus, which is in the zodacal belt but was never considered.
The zodiacal signs considered in astrology had a correspondence with the constellations having the same name millennia ago, but the precession of the equinixes makes signs progressively shift along the zodiacal constellations, in a cycle of 25,800 years. For example, when someone who was born in our times affirms to be a “Capricorn”, he/she was born when the Sun was in the constellation of Sagittarius. The shift affects all signs.
This simple instrument is intended to highlight this incongruence, i.e. that astrological signs have no link or correspondence with anything having to do with the real universe.
Future Pilot’s Starter Kit
A completely new product ready for production
This introductory kit is targeted at aviation enthusiasts and future pilots. The box includes more than 30 items including standard computing and plotting instruments, maps, and a brochure with an introduction to the aviation sector and the activity of flying. There is also a 224-page book detailing all aspects of aviation, piloting, navigation and radio telephony, with an extra 50 inserts to allow readers to delve further into technical and historical issues.
View a presentation of the Future Pilot Starter Kit
«If you are thinking of earning your pilot certificate, or simply interested in aviation, Cesare Baj’s Future Pilot’s Starter Kit is perhaps the most engaging body of work on the market today.
It has everything: aviation history, piloting procedures, cockpit equipment, aerodynamics – and even a paper airplane.
Anyone wanting a complete introduction to flying can’t afford to be without it.»Thomas A. Horne
“AOPA Pilot Magazine” Editor-at-Large
Turbine Pilot editor
Mathematicus – The game of mathematics
Mathematicus is a one-of-a-kind game that debunks the legend that mathematics is a hard, sterile subject. Mathematics is undeniably the foundation of science and all technical matters, but it is also entertaining and offers an incredible variety of experiences.
Mathematicus can be played in “basic”, “intermediate” and “advanced” modes. This is possible as each card has questions with four progressive difficulty levels; in this way, players with diverse knowledge can play together.
The squares on the board present a series of mathematical curiosities which, although irrelevant to the game, are provided to illustrate how vast and interesting the world of mathematics is.
The themes featured on each square are developed in the 176-pages book.
The advanced game introduces the player to the world of computing with the aid of ancient computing instruments, namely Napier’s Bones and the Slide Rule, as well as an initiation to ancient and exotic numbering systems (Babylonian, Egyptian, Roman, Arabic, Mayan, Chinese), the binary system and mental calculus.
The game additionally offers ample opportunities for experimentation independently from the game.
The booklet explains how to write and decode secret messages, how to prepare an interstellar message, how to prepare quipu in the style of the Incas, and how to wow friends with magical mathematical games, to name just a few possibilities.
Napier’s Bones
Dating back to their invention in 1614, for three centuries these calculation rods were the chief instrument used to perform multiplications and divisions.
The set of rods is an exact reproduction of the original version designed by Napier as described in his work Rabdology.
The attached booklet provides complete instructions on how to perform mathematical calculations, historical information and interesting snippets of information on the subject.
Stomachion
1500 years prior to the invention of the Chinese Tangram, Archimedes described the Stomachion. This game was gradually diffused throughout the Mediterranean from the second century b.c.e. onwards, initially in the Greek zones and then in the Roman ones.
The attached booklet presents interesting mathematical features surrounding this artefact as well as recounting the eventful history of Palimpsest, a recently discovered ancient manuscript containing various Archimedes’ missing works that had been overwritten with liturgic texts, among which was the Stomachion.
Promptuarium Multiplicationis
This rare and unusual tool, invented by John Napier in the 17th century and detailed in his work entitled Rabdology, was designed to facilitate multiplication.
The attached booklet provides historical information, interesting facts, the tool’s mathematical features and instructions for use.
Constant width solids
Particular shaped solids, designed by the mathematician Franz Reuleaux, which can be used for experimental purposes. The attached booklet describes some applications, such as the Wankel engine that uses a rotary design, or the drill bit that produces square holes.
Workshops
Cesare Baj thinks that outdated technologies deserve attention because they are an element of our cultural heritage and have always something to teach.
In addition, they can have an educational value. This is more valid for those technologies that allow to manage a process of construction from raw materials to the finished product.
The same is valid for experiments that made the history of science, whose repetition is highly formative.
These are workshops Cesare Baj proposes to schools and associations.
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Calculate like our ancestors…
Design and construct a slide rule, based on logarithms, to determine one’s own weight or the weight of any object on the surface of the planets and main satellites of the solar system and on the potentially habitable extrasolar planet Kepler-22b
Click here to view the program of the workshop
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Measure the Earth with a stick
On the footsteps of Erathostenes, an amusing scientific experiment to make at school
A Babilonian slide rule
Read the short story
“A Babylonian slide rule”
by Cesare Baj
A Babylonian slide rule… an “impossible” archaeological find
As a scholar of analogue calculus familiar with the history of slide rules, Cesare Baj is a member of the Oughtred Society, the international association based in the United States dealing with such issues.
Through his study of Babylonian mathematical tablets, he has been able to show that this civilization set out studying logarithms without using them, meaning that they already had the necessary knowledge to produce a logarithmic slide rule two millennia prior to Napier inventing logarithms.
He then proceeded to design and build an example of a “Babylonian” logarithmic slide rule functioning in the sexagesimal system, using the exact knowledge existing in ancient Mesopotamia.
The “find” was authenticated by fictitious but credible scholars in the field, and used in a fantastic archaeology experiment simulating an archaeological expedition discovery.
The news was rapidly revealed as fake in order to illustrate how gullible people can be tricked when provided with well-constructed ‘scientific evidence’.
This initiative reflects the spirit of the CICAP, of which Baj was a founding member. The CICAP is the Italian counterpart of the American CSI (Committee for Sceptical Inquiry) and of many other sceptic associations operating around the world, for example the Association for Skeptical Enquiry based in the UK.
The David Campbell-Harris “Future of Communication” award
In 1986 Baj was presented with the “Future of Communication”award from the J. Walter Thompson agency, in recognition of his report on “Second generation slide rules – Interesting applications in the field of mass communication and advertisement of a sophisticated technology of the past”.
In the report, Baj described how slide rules, technical instruments that fell into oblivion in the mid 1970s, could have a second life in mass communication and the education and advertising sectors.
His production of kits and gadgets, sold in hundreds thousand copies across four decades, is a clear demonstration that slide rules really do deserve a second life and still have something to tell us.
