# Napier Abacus | Science game

We were thinking In the last week Meters and second, the relationship between our unit of length and the unit of time. Well, the relationship could not be more straightforward: the half-life of a pendulum oscillation with 1 meter of thread is almost exactly 1 second (to be exact, the thread should measure 99.4 centimeters, as determined by Mersen in 1664). In fact, before the classical definition of the meter was imposed as ten millionths of a quadruple of the land meridian, first the protein and then the dollar proposed the unit of measurement as a “pendulum length of seconds”. Is called. Its oscillation period (tour: tick tock, to understand us) is 2 seconds.

In principle, the pendulum is a much easier way to determine the longitude of a unit than to measure the meridian of the Earth. Why do my brilliant readers believe that the second criterion was chosen?

Tito Livio Puertini (1617-1681), a skilled and far-sighted man, failed to impose his unit structure on both, but he did impose the name “meter” on the unit of length. Not only were his contributions theoretical, he also invented and built unique devices such as an airplane (a team member was able to fly with a cat) and a counting machine.

According to last week’s ice cube, when it floats, it displaces water equal to its weight, and if it dissolves it turns into water, which occupies exactly that amount, so that water does not come out of the whole glass. Intuition. In fact, the water level will decrease invisibly as it cools, reaching its maximum density of 4ÂșC.

In the water and wine problem, if you pay proper attention, you can see that there is the same amount of alcohol in a glass of water. Each glass has the same amount of liquid activity as before (since we remove one tablespoon and add another); Therefore, the amount of alcohol in the first class is equal to and less than the amount of water.

My brilliant readers will not fail to appreciate the similarity of these two aquatic puzzles, which apparently have nothing to do with each other.

### Abacus and logarithm

Returning to the protein, his pioneering computing machine was based on the Napier abacus, which is a good excuse to talk about the Napier.

John Napier (1550-1617), the great Scottish mathematician Mercystan, is, above all, known as the father of the logarithm, which greatly simplified complex astronomical calculations and doubled the lifespan of astronomers. Simplifying the calculations was one of Napier’s main concerns, as he not only created the first table of the logarithm, but also popularized it by using commas to distinguish the decimal from the whole of the numbers, and created the abacus with his name.

The Nabirian abacus consists of a board and ten stems with one edge, the height of which corresponds to the height of the board, so that they fit exactly into it. The left edge of the board is divided into nine squares from 1 to 9. The stems are also divided into nine squares; The upper bouts featured two cutaways, for easier access to the higher frets.

And in the picture below we see a simple example of the use of abacus, from which we can calculate its functionality, as well as its relationship with loops. Is it possible?

Carlo Frabetti A writer and mathematician, a member of the New York Academy of Sciences. He has published more than 50 popular scientific works for adults, children and young people, including ‘Damn Physics’, ‘Damn Mathematics’ or ‘The Great Game’. He was the screenwriter for ‘La Bola de Crystal’.