How Long Would It Take To Fall Through The Earth?

Let’s say we’ve got a hole through the earth and it goes from pole to pole. There’s also no air – otherwise you’d reach terminal velocity quickly because of air resistance. Also, assuming the earth has the same density everywhere and is perfectly spherical, you jumped in right into the hole. So how long would would it take for you to reach the other side of the hole?

 

Source: https://scienceswitch.com

Annunci

Science

Leonardo da Vinci Science - Anatomical Studies

Leonardo da Vinci was a renowned scientist, often ahead of his time with the scientific discoveries he made and the theories he formulated

This article explains Da Vinci’s scientific method, how it related to the cultural and scientific climate of the time, and some of the key scientific discoveries that it generated.

What was Da Vinci’s Scientific Method?

Da Vinci is often described as being a true Renaissance polymath: that is, a person who wishes to understand all branches of knowledge. As such, Da Vinci is likely to have viewed scientific research as a complement to his researches in art and languages as well as to the study of theology.

In short, science in his world view was probably one of several branches of knowledge that he wishes to master in order to achieve a well rounded education. Da Vinci’s scientific method consisted of a mix of observation of the world around him and the physical experimentation with, and construction of, new inventions, aided by preliminary sketches.

Though his hunger for all types of new knowledge and discovery planted him firmly at the heart of what many consider to be Renaissance values, in another way Da Vinci was something of an unconventional scientist. This is because, despite the fact that university culture was flourishing in Italy during his life time, he never attended a university (and thus had no formal education in mathematics, despite being a great mathematician).

It could be argued that this lack of a formal structure to his education is precisely what enabled Da Vinci to be such a free thinker and such a good scientist. Da Vinci’s scientific interests, inventions and experiments spread out vastly into numerous different areas of science. Not only was he interested in chemistry and geology but also in astronomy, pyrotechnics, biology (or zoology), human and animal anatomy and mechanical engineering. Da Vinci’s scientific endeavours were so ahead of his time that he has anticipated many devices that we consider to be ‘modern’.

Two key examples of this are the calculator and solar panels for generating electricity. Now, let’s take a look at a few of Leonardo Da Vinci’s key scientific inventions and findings. This is most certainly not an exhaustive list of his scientific achievements but is more just to give a flavour of the types of scientific work that he applied himself to.

Da Vinci’s Studies in Anatomy

Da Vinci made many detailed drawings of both human and animal anatomy. His famous drawing of the Vitruvian Man is an example of his interest in the proportions of the human body. This drawing is a good example of how several of Da Vinci’s scientific works could also be considered works of art. There is no doubt that Da Vinci’s in depth knowledge of the human anatomy beneath the skin enabled him to create such dynamic and realistic portraits of human beings in his paintings.

Da Vinci produced numerous anatomical studies in his sketchbooks, and it is clear from them that he was very interested in the relationship between skeletal muscle and movement. He writes in one journal of discovering how pulling gently on a single muscle fibre can make a cadaver’s whole arm, move, for instance. Gestation was another topic that keenly excited Da Vinci’s medical mind: he studied the way in which the foetus develops in the womb in such detail that his drawings remained useful for several centuries afterwards. Finally, Da Vinci also had a significant interest in comparative anatomy.

That is to say, he was interested in comparing the anatomical make up with human beings to those of other animals (especially horses). This interest in comparative anatomy, combined with Da Vinci’s studies of fossils, may have led him to hit upon a rudimentary theory of evolution.

However, it would very likely have been considered a heresy had he published this theory or spoken about it in public, so it is likely that if he did formulate such a theory that he was likely to have kept his ideas to himself. Galileo Galilei, another important early modern scientist, was captured, tortured and condemned by the Roman Inquisition for stating his scientific belief in a heliocentric solar system (i.e. a solar system where the earth and planets orbit the sun rather than – as was thought at the time – the sun orbiting the earth).

Da Vinci’s Relationship with Geology

Da Vinci traced his interest in geology back to a powerful childhood memory that he had of entering a cave near where he was living and seeing, by torchlight, bands of different fossils in the rock. This suggested to him that at one time the cave – which was high up in the Apennine Mountains – was once below sea level. Leonardo studied the way in which sedimentary rock was formed and this led him to dismiss the notion that it was Noah’s Great Flood that caused the sea shells to be thrown up into the mountains.

However, because these ideas would be very likely to have been considered heretical at the time as they were contrary to the Bible’s teachings, it is possible that Da Vinci was dissuaded from pursuing or publishing any further formal studies in geology.

Hydrodynamic Studies

As a young man, Da Vinci used to construct numerous different objects thanks to an uncle who taught him how. Da Vinci thus made a very good self taught civil engineer. He constructed several inventions that were deemed to be very useful by the state of the time, including bridges and several catapults. One significant aspect of his studies in civil engineering involved hydrodynamics.

Da Vinci created several machines that were designed to control the flow of water, including a corkscrew shaped contraption (based on ancient Roman hydraulic systems) that was able to move water in a vertically upward direction.

Overview of Some of Da Vinci’s other Scientific Discoveries

From his perpetual motion machine to his theories about the relationship between light and opaque bodies, Da Vinci’s scientific discoveries are all totally fascinating. He used his geometrical investigations to understand more about perspective (and subsequently applied this knowledge in his works of art), for instance, whilst his love of flowers and plants led him to study and to sketch the makeup of trees and flowers with as much skill and dedication as he devoted to the inner workings of the human body.

He came to some surprising conclusions, here. For example, he wrote as if it was an axiom that if at any point during a tree’s life you measured the thicknesses of all of its branches (excluding the central trunk) and added those thicknesses together, the final value would equal the value for the thickness of the trunk itself.

Discovering Da Vinci’s Scientific Mind through his Journals and Publications

Da Vinci’s plethora of sketch books and journals are a window onto his scientific mind. Usually, Da Vinci wrote in his journals and annotated his scientific diagrams with mirror writing (i.e. writing that could be read by placing a mirror up against the page). He also published one scientific work. This was a mathematical treatise on proportion which was published in 1509.

Da Vinci co wrote it with one of his friends, the mathematician Luca Pacioli, and it was entitled De divina proportione. Many of Da Vinci’s scientific discoveries were not made manifest by means of the printed word, however, but by practical demonstrations. He loved to create models as well as life size working inventions of his bridges, catapults and other war machines.

He also worked physically with lenses and other optical devices. Da Vinci also claimed to have created a formula for a perpetual motion machine. This is a machine that stays in motion once it has been started, without any need for a further supply of energy and without losing any energy or momentum due to friction or air resistance.

To this day, scientists and engineers would love to know how to create a highly energy efficient machine such as this one. However, thus far, this has been one of Da Vinci’s discoveries (assuming that he truly had concocted a way to make such as machine) that continues to elude the minds of modern scientists.

http://www.leonardo-da-vinci.net/science/

Annunci