Science questions for kids | Is there such a thing for sure that hasn’t happened yet?

Arvi Asikainen, 7

No be. Certainty can mean two different things, but in neither sense is it completely certain that something that has yet to happen will happen.

First of all, for sure can mean complete conviction. If you are absolutely certain in this sense of something, there can be nothing else that you are more certain of.

For example, you may be very sure that the sun will rise tomorrow. However, you can’t be completely sure about it, because you are more sure that you yourself exist, or that at least something exists.

Certainty can also mean that it is impossible to make a mistake. However, it is possible that the sun will not rise tomorrow, and therefore you will be wrong about that. Maybe the earth will stop spinning at night, and the sun won’t rise tomorrow.

The fact that the earth would stop rotating is of course very unlikely. However, it is not impossible, because we cannot completely exclude the small possibility that some force would stop the earth’s rotation.

So there are very few things we can be absolutely sure of. Future events are not included.

Markus Lammenranta

docent of theoretical philosophy

University of Helsinkio

Why does the coat of arms of Finland have a lion and not, say, bears? There aren’t even any lions here?

Niilo Vehmanen, 7

The beginning originally coats of arms were designed to honor rulers and warlords. The oldest state coats of arms are around 800 years old. Most of the coats of arms of European countries have an animal.

Almost all have an animal motif, a lion, an eagle, or both. The subjects have ended up being some kind of predatory kings of the animal kingdom, because they have been apt to emphasize the strength of the subject.

A lion is an exotic animal from a European perspective, unlike a bear. Thus, it has had a special value as a subject. Heralds have also imitated each other, so the same motifs are repeated in coats of arms.

In addition to Finland, Estonia, Norway and Denmark also have a lion coat of arms. In addition to lions, Sweden has a tiny eagle on its coat of arms.

In none of these lion emblem countries have lions ever been found in the wild. Eagles, on the other hand, live in different parts of Europe. Although the two-headed eagle of the Russian coat of arms is not encountered in the wild.

At the end of the 16th century, the area of ​​present-day Finland belonged to the Kingdom of Sweden. At that time, a spectacular coat of arms was designed for the Grand Duchy of Finland to describe the province’s status as part of the kingdom.

The lion was an understandable choice, because lions were prominent in Sweden’s coat of arms too, and the eagle was out of the question.

The lion coat of arms gained general popularity as a symbol of resistance in Finland at the turn of the 19th and 20th centuries, when Finland belonged to Russia. After Finland became independent in 1917, it was clear that the national emblem would be a lion.

Tuomas Tepora

University researcher

University of Tampereo

What makes a reflector reflect?

Sara Elomaa, 7 and Laura Elomaa, 9

Very materials that reflect light are, for example, metals, such as the familiar aluminum foil from the kitchen. Reflectors use a very thin metallized surface, like mirrors, so very little metal is needed.

The better the light is reflected, the greater the difference in the refractive index between the air and the reflective material. The refractive index describes how light travels in any substance. Air has a low refractive index, while metals have a high refractive index.

It is essential for the reflector that the light is reflected exactly in the direction of entry, and not where it happens. That’s why a prism-shaped structure is molded into the reflectors, where the light is reflected from three different surfaces and finally goes back to its direction of entry.

Another option is to use transparent glass or plastic balls with a metallized back surface. A spherical structure is used in reflective fabrics and a prism structure in hard plastic reflectors.

The use of a reflector as a safety device is a Finnish invention. It was invented in the 1950s by a person from Pert Arvi Lehti.

Juha Toivonen

professor of physics

University of Tampere

Do monkeys or other animals have separate milk teeth and permanent teeth like humans?

Puro Mäkinen, 6

Most of them mammals have milk teeth that change into permanent teeth.

This is the case, for example, with the monkeys mentioned by Puro. Their baby teeth are very similar to permanent teeth, but smaller in size like humans.

Milk teeth and permanent teeth are also present in cats, dogs, sheep, reindeer and moose.

Exceptions to mammals are manatees, kangaroos and elephants, which can change their teeth many times. New teeth grow when the previous ones have been worn down.

Also, rodents, such as mice and rats, do not develop baby teeth and permanent teeth separately. The teeth that develop for the chick will last the rest of its life.

The chisel-like front teeth of rodents grow continuously as they wear down with use. Exceptions to rodents are the field vole and the forest vole, whose molars also grow all the time.

Likewise, reptiles and fish do not develop milk teeth. They don’t develop permanent teeth either, instead the teeth are constantly renewed.

Jussi Viitala

nonfiction writer, biology researcher

Send the question, the questioner’s full name and age to [email protected]. The column is edited by Touko Kauppinen and Juha Merimaa.