Exploring the Lotus Effect using Candle Soot

Also this Instructable is the results of some home experiments that I did some time ago (see also my previous article). It shows how to prepare these simple surfaces and make some interesting observations with them. As the previous two Instructables, my family help me a lot in preparing it in the very short time of one day. So a big thank you to my wife, Francesco, and ,in particular, to Leonardo.

Hydrophobic and super-hydrophobic surfaces are ubiquitous in the natural world. You do not need to search much to find good examples: just walk out in your garden after a light rain and look at the plenty of weed leaves pearly decorated by water droplets. If you have an ornamental pond, you may have even the chance to see floating better examples of plants having a super-hydrophobic surface. Notably, wettability in Nature is present in a different form that subtle differences in the function and effect on the water droplets. Plant leaves need to keep their surfaces clean for light-harvesting efficiency. A water repellent leaves let water drops roll over its surface and mechanically removes dust particles. This effect was first noted on leaves of the Lotus plant, and for that reason, it is also called the Lotus effect.

Several novel technological materials exploit the properties of super-hydrophobic. For example, in your kitchen, Teflon pans are used to avoid sticking food residuals and therefore easily cleaned. Your car windows are teated to let the water easily roll over the surface. 

Candle soot is an artificial material that is easy to produce and can be used to demonstrate some of the properties of the (super)-hydrophobic surface existing in nature.

The Mighty Roto-Microscope

I am happy to announce our second Instructable project. As the first one, it was a long standing idea that was rolling in my mind since a long time. The current limited travelling mobility due to the COVID offered more time to develop this idea during my vacation. In a joyful collaboration with my son Leonardo, we managed to realize this useful device in a very short time.

This project aimed to develop a device that integrated with a cheap USB microscope allows taking 3D pictures of small samples. The project is meant to be an education STEM activity to learn using Arduino, 3D image reconstruction, and 3D printing by creating a useful piece of equipment for doing some exciting science activity. Like my previous project, it is also a moment to share good and educative time with my family and in particular, my elder son Leonardo that helped me in creating this instructable and evaluating the device as an enthusiastic STEM student. This time, also my lovely wife helps me to make a video of the assembly of the equipment!

The roto-microscope allows controlling the position of a simple USB microscope around the sample. This allows to take accurate pictures from different angles and not just from the top as in the traditional microscopes. This is not a new idea as there are professional microscopes. However, this device means to be affordable for a student and still provides some similar results and a lot of fun in building it. Other similar and excellent OpenSource projects are available (see, for example, the Ladybug microscope, the Lego microscope, and the OpenScan project), our project adds an additional option and I hope that you enjoy making it as we did!

If you find it an interesting device then instructions how to build it are on our Instructable.

The Magic Sand Slicer

We have published for the first time a project on Instructables: a website specialised in publishing interesting DIY projects by an effervescent community of makers and educators.

The project is called the Magic-Sand Slicer and it is an education project initially conceived as a STEM activity to learn using Arduino, a 3D printer, and some exciting science. It is also a collaboration with my son Leonardo who helped me in evaluating the device as a STEM student. We have learned a lot together, and we want to share the results of this long journey. This project aims to create a device that automatically makes sections of a cylinder of easy-to-cut colored material. That can be used for practicing 3D image reconstruction of the colored blogs hidden in the column. The so-called Magic-Sand (c), also known with other trademarks names, becomes suitable for this experiment.
What is the point of making pictures of thin layers of sand and then reconstructing it digitally? Is it just for the fun of it? It varies on who is using it. However, students and teachers from different disciplines (e.g. geology, biology, medical) can find it a helpful education device to practice with image reconstruction from the serial sections. It could also be of interest to a geologist interested in sedimentary material plasticity to study rock and the secrets it beholds, or to a process, engineering to emulate the packing of fine granular materials. Finally, an artist can make a fantastic program of unraveling magic forms generated by packing colored sand. 

I was surprised that the project got so much interest in very short of time and I thank the Instructable community for their nice welcome! If you like to know more about the project (and try it!) then you can read our instructable here.

I also just realized that the Instructable was reviewed in the Arduino blog site by the Arduino team!

Modelling Forms in Nature: Easter Chocolate Eggs 2021

This year, your Highness, we will be featuring square eggs.
Peter Carl Fabergé

The Easter Math Bunny is back again, and he is talking again of … eggs!

Two years ago, I ended my blog with a question, “What about chocolate egg shapes?” It is now the time to give some answer. If you have read my previous articles, I and many scientists and artists have been caught by the shape of the bird eggs. Several models have been proposed to reproduce the silhouette of bird eggs. Baker [1] proposed a simple two-parameters mathematical model based on projection geometry that revealed to be versatile and accurate in producing the shapes of a large variety of bird eggs [1]. More recently, the model was used to perform a systematic and comparative study of the shape of 1400 bird eggs species [2].

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The Dandelion (Taraxacum Officinalis) and OpenCV

The dandelion’s pallid tube
Astonishes the grass,
And winter instantly becomes
An Infinite Alas —

The tube uplifts a signal Bud
And then a shouting Flower, —
The Proclamation of the Suns
That septulture is o’er.

– Emily Dickinson

The yellow flowers and the delicate and beautiful florescence of Dandelion catch the attention of both romantic and curious souls. The aerial consistency of the fine silk decorated seeds that glance to the sunlight as crystalline material became the favourite subject of inspired photographer and the toy of amused children. Beside the grace of its forms, other interesting and curious secret is hidden in its phloem fluids. In fact, if you cut one of the stems of the plant a milky sticky liquid will flow out of the wound resection. This latex is going to polymerize at 30-35 oC in few minutes in a yellow-brown quite solid mass. Around the year 1982, I have annotated this observation but I could not find in my later notes further follow-ups study on the topics. It was a casual observation but I didn’t know at that time that this latex is indeed very useful. A variety of the Taraxacum (Taraxacum koksaghyz, Russian Dandelion) was used in Russian and American to produce a replacement of the natural rubber from Brazil during the WWII that was in shortage because of the war. Now days, many researches are in progress to exploit the lattice of Taraxacum and also Taraxacum brevicorniculatumas a convenient replacement of the rubber plant lattice. A recent study has shown the presence of rubber particles in the lattice of these plant in 32% proportion composed prevalently by poly(cis-1,4-isoprene) at >95% of purity (www.biomedcentral.com/1471-2091/11/11). The brownish lattice condensate that, as I reported in my note, forms after exposing for several minutes the latex to the air, is caused by the presence of the polyphenol oxidase (PPO) enzyme that produces the fast coagulation of the latex by catalysing the oxidation of polyphenols. Genetic engineer the plant, it is possible to reduce the amount of PPO in the latex making economically competitive the use of this resource for the production of latex.

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Modelling Natural Shapes: (Easter) Eggs 2020

One year ago, I wrote an article about the modelling of the egg shapes, promising at one point to come back on the topics. A next step in studying eggs shapes is to look to real one or a copy of it. A happy occasion for experimenting with the model using three-dimensional graphics and 3d Printing! That is a natural indeed step: take half of the symmetric curve representing the egg shape


where T and \lambda are two parameters, and rotate it around the central axis

\begin{aligned} x'&=&x\\ y' &=&y*cos(\theta) \\ z' &=& y*sin(\theta) \end{aligned}

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Modelling Patterns and Forms in Nature II: (Easter) Eggs

When you start with a portrait and search for a pure form, 
a clear volume, through successive eliminations, you arrive 
inevitably at the egg. Likewise, starting with the egg and 
following the same process in reverse, one finishes with 
the portrait.


Easter is coming and what better time to talk about eggs!

During my recent mathematical explorations of natural shapes and forms, my attention has been catched by the shape of birds eggs. In the interesting book by J. Adams, A Mathematical walk in Nature [1], you can find a short review on the different mathematical modelling approach to describe the shape of an egg. Among them, the geometrical one by Baker [2] is revealed one of the most versatile as it can very accurately reproduce the shapes of a large variety of bird eggs [2]. More recently, the model was used to perform a systematic and comparative study of the shape of bird eggs. This study, published on Science magazine [3], a two-dimensional morphological space defined by the parameters of the Baker’s equation, has been used to show the diversity of the shape of 1400 species of birds. Combining these information with a mechanical model and phylogenetics information, the authors have shown that egg shape correlates with flight ability on broad taxonomic scales. They concluded that adaptations for flight may have been critical drivers of egg-shape variation in birds [3].

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I Primi 150 Anni della Tavola Periodica degli Elementi

Che la nobiltà dell’Uomo, acquisita in cento secoli di prove e di errori, era consistita nel farsi signore della materia, e che io mi ero iscritto a Chimica perché a questa nobiltà mi volevo mantenere fedele. Che vincere la materia è comprenderla, e comprendere la materia è necessario per comprendere l’universo e noi stessi: e che quindi il Sistema Periodico di Mendeleev, che proprio in quelle settimane imparavamo laboriosamente a dipanare, era una poesia, più alta e più solenne di tutte le poesie digerite in liceo: a pensarci bene, aveva perfino le rime! 

Primo Levi, Il sistema periodico

Il 6 Marzo del 1869 il chimico russo Dmitri Ivanovich Mendeleyev presento’ alla Societa’ di Chimica Russa, una comunicazione dal titolo La dipendenza delle proprieta’ degli elementi chimica dal peso atomico. In questa storica comunicazione, Mendeleev pesento’ una tabella in cui organizzava gli elementi chimici allora noti. Questa tabella segno’ anche la fama del suo autore poiche’ fu la prima versione della moderna tavola periodica degli elementi chimici.

La tavola periodic degli elementi di Mendeleev. I trattini rappresentano elelmenti sconosciuti nel 1871. (fonte della figura: wikipedia)

Mendeleyev, preparando una seconda edizione del suo libro di chimica, stava cercando un modo per classificare gli elementi chimici allora conosciuti (53 ovvero meno della meta’ di quelli che conosciamo oggi) per fare chiarezza sulle loro proprieta’. In una nota, Mendeleyev racconta che l’ispirazione gli sia venuta in sogno (non e’ la prima volta che Orfeo suggerisce a chimici le loro grandi scoperte scientifici!) [2]:

I saw in a dream a table where all the elements fell into place as required. Awakening, I immediately wrote it down on a piece of paper.

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Frosinone and the Ciociaria

Glie musèu
Tra glie campanìle i l'Annunziàta,
'Ntòcce prima della uìa ‘Ngelòne,
Stamatìna sò fatte 'na fermàta
Pè rattaccà le strengh'a strucenòne.
Me uànne gli'òcchie doppe 'na utràta
I uède, tutt'a giòrne, nè salòne
Addò 'na raccòta sta urdenàta
De prete, crete, pièzze de matòne,
Cule de uàse, de pile, de pignàte,
Màneche de recciòle i de bicchièra
Ancòra prima de Nuè 'mpastàte.
Quante sècule,frà, che sò passàte
'Nche gli'Ome a trebbulà 'ncim'a sta Tera
I ch'è remàste ? Ddù cocce smenuzzàte.
              Irèno Da Vialìra (Poeta ciociaro)  

I am European of Italian nationality. I very proud of my background but, unfortunately, my carrier put me in an orbit that does intersect my country only during my holiday vacations. In these close encounters, my landing site is Frosinone. When not-Italian acquaintances want to know about my Heimat, most of them are puzzled about the name and location of my hometown. Usually, I help them to overcome the understandable disorientation by giving as reference Rome and telling them that my birthplace is somewhere 80 km in the South of the Caput Mundi. Last year (2018) my hometown soccer team (Frosinone Calcio, nicknamed Canarini, The Canaries, for their home colours)) moved in the first league (A) of the national soccer championship. So, let see if this success will help to raise its notoriety!

It is a long time that I would like to write about Frosinone. However, in this article, I won’t write about the success of the Canarini football team but about my hometown and the rural place in central Italy where it is located.

In the province of Frosinone, there are many historical famous towns such as Anagni that has the exquisite Anagni Cathedral with its museum, Alatri with its megalitic Acropolis, Ferentino another megalytic city with also a beutyful Romanesque Duomo, Veroli and the closeby Certosa of Trisulti that has been recently on news spot for the sadly attempt to trasform this wolderful medieval santuary of christianity and culture to a private business when instead it should be preserved and nominated instead as an humanity heritage. I will talk about these town in other articles. This just to mention some of the famous towns and cultural places in Ciociaria.

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Retro Programming II: the Amiga and the Computational Beauty of the Leaf

In my archeological exploration of old computer files, I came across to another simple but interesting Amiga Basic program that I programmed in 1989. It is named “Foglie”, the Italian name for leaves. It was an attempt to explore some ideas of functional plant morphology modeling. The stimulus comes after the reading of the paper by Karl J. Niklas on issue 213 of Le Science (the Italian edition of the Scientific American magazine [1]). The article titled “Computer-simulated plant evolution” and was a description of the modeling of plants to study their interaction with the environment. It was a fascinating paper, and still simple and primitive graphics was catching my imagination. Nowadays the field of digital morphology come to an age (just to mention one, Avatar) and we can have an idea of this progress in the level of realism in movies, video games, TV programs. My curiosity an interest has been always caught by the form and shapes of the organism and the structure of leafs nervation was an intriguing pattern very much related to my acquaintance with the fascinating fractals objects, another recurrent topic in the pages of scientific magazines of the period.

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