Children ‘s science questions When and who came up with the countdown?

Louna Urhonen, 10

Different there are very different ways of expressing numbers in cultures, and those ways are reflected in how calculations are made.

Counting down is a typical method for the so-called decimal system used by us and around the world. It expresses all numbers in strings of ten characters – 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.

This notation originated in India around the year 500.

It is not known who first invented the underestimation, but it has probably been used early in India. It has been natural to perform addition, subtraction and multiplication of multi-digit numbers by subtraction when no calculators have been used in ancient times.

The oldest printed calculus dealing with calculus appeared in Treviso, Italy, in 1478. The opus, known as Treviso’s Arithmetic, presents the principles of decomposition in depth and in exactly the same way as it is taught today. There is no information about its author.

Matti Lehtinen

docent in mathematics

university of Helsinki

Why are Christmas lights called Christmas lights, even though they are used a lot before Christmas and long after Christmas?

Robert Kajanne, 10 and Joel Kajanne, 8

With the word Christmas light has a long tradition. The word Christmas light or festive light has been used in the Finnish language since the 19th century.

First, they meant candles, lanterns, and torches lit in honor of the feast. In the early 20th century, electric lights were also used in the model of the great world.

The term decorative light was also used early on. However, it was used especially for neon lights.

From time immemorial, people have thought that the lights look especially beautiful during the darkest part of the year. We also want to separate the festive time from ordinary everyday life by decorating homes and the environment. Most of the light decorations are procured for Christmas, and it is easy when there are more and more attractive and affordable products on offer.

The lights are enjoyed other than at Christmas, but from old memory they are often called Christmas lights even then. The term decorative light is also widely used today. There has also been some talk about garden lights and winter lights.

The novelty of the 21st century is seasonal light. It may be a word that will soon become a more general designation.

Kaisa Häkkinen

Professor of Finnish

University of Turku

Did the dinosaurs have a pole?

Tyko Heinilä, 4

No had been. The umbilical cord is present only in humans and other mammals whose earliest development occurs in the mother’s womb.

The navel is actually a scar. It is located at the point on the abdomen where the tubular umbilical cord has been attached. The umbilical cord runs from the mother’s placenta to the fetus inside the womb. The placenta is an organ that carries oxygen and nourishment to the fetus and carries away unnecessary waste products.

Dinosaurs did not need a umbilical cord because, like other reptiles, they multiplied by laying eggs. The eggs of the dinosaurs were surprisingly small for the large size of the animals, usually less than 30 centimeters long.

Some petodinosaurs had colorful spots and other patterns on the surface of the eggs as in the eggs of current birds, while no color patterns have been found in the eggs of plant-eating dinos.

Timo Vuorisalo

Associate Professor of Ecology and Environmental Protection

University of Turku

Why are coins round and not squares or stars, for example?

Liina Kuusinen, 5

Round the coin is easy to manufacture, transport and handle.

Coins go through the manufacturing steps well when the corners don’t go the way of the other corners. So the coins conveniently rotate against each other.

The coins produced are often wrapped in paper rolls. Star or square coins would require a more complex packaging system.

The round shape is also comfortable in the hand and easy to handle. One can imagine what the corners of a star or a square would feel against the palm and fingers, for example, when a coin is pressed in a fist. Sharp corners could also easily make a hole in your pocket or purse.

In addition, the round coins roll easily, so they work well in vending machines, for example.

However, not all coins are completely round. The British 50 pence coin, for example, is hexagonal, and the 20-cent notched shape is called the Spanish flower. It is ultimately up to states to decide what their coins will look like and what shape they will look like.

Jaakko Koskentola

curator

Bank of Finland Money Museum

Heini Pylväläinen

technical expert

Mint of Finland

Why does a bubble blown into a milk glass last longer than a soap bubble?

Helmi Petäjä, 9

Soap bubbles will always decay before long, even if they hit nothing. The reason for this is that the bubble is drying up.

The rate at which a bubble dries is affected by its composition. For example, if you add sugar to a soap solution made from dishwashing liquid and water at home, the bubbles will become more durable.

Namely, sugar increases the density and thus the elongation of the soap bubble and reduces the evaporation of water. Commercial soap bubble liquids often use glue and glycerol because they also improve the durability of the bubbles. The reasons are largely the same as for sugar use.

You can really get bubbles in your milk. Because they are usually quite small, a comparison with soap bubbles is difficult. However, it is possible that milk bubbles are a little more durable.

Evaporation on the surface of the milk may be less. The fat in the milk can also reduce the drying of the bubble. However, careful scientific examination of the bubbles would be needed to ensure that the milk bubbles dry out and cause them. That has probably not been done.

Tom Kuusela

University Researcher in Physics

University of Turku

Send the question, the full name and age of the questioner to [email protected]. The column will be edited by Touko Kauppinen and Juha Merimaa.