Science questions for kids | Why does the fat feel colder on the back than elsewhere?

Samuel Taskula, 9

Divers fats and creams mainly contain water, but also other easily volatile ingredients such as oil.

When those ingredients come into contact with the skin and the air, evaporation immediately follows. Evaporation binds, i.e. absorbs a little heat from the skin. That explains the momentary cool feeling.

However, greasing skin areas seems to feel different for different people. Our sense of touch can therefore vary.

For some, fattening the back may actually feel colder than the rest of the body.

It may be because they have a lot of sensitive nerve endings on their backs that sense temperature differences. Information about temperature travels from nerve endings along nerve pathways to the brain's hypothalamus.

The area to be fattened on the back is also large compared to, for example, arms and legs. Evaporation may be more abundant in the back area, which may cause a greater sensation of coldness.

Nicolas Martinez-Majander

specialist in neurology, docent

Helsinki University Hospital

Why are there so few women in the presidential candidates, even though there were many women candidates in the parliamentary elections?

Nelli Nyman, 9

In the parliamentary elections parties are allowed to have several candidates, for example in Helsinki 23. Then there can be many types of people.

However, each party or voter association can nominate only one candidate for the presidential election.

When you can only ask for one, the parties think carefully about who would please the voters. The president's task is to manage Finland's relations with other countries. That's why many voters think it's important that the candidate has experience.

In politics, it used to be common for women to focus more on domestic issues, such as deciding on hospitals and schools.

The importance of foreign policy expertise is well reflected by the fact that so far the only female president Tarja Halonen was also the first woman to serve as foreign minister.

On the other hand, not everyone necessarily wants to be a candidate, even if asked. Former Prime Minister Sanna Marin would certainly have been a popular candidate, but he did not want to run.

It's good that the larger number of male candidates seems disturbing. It shows that equality is considered an important issue and that politics does not want to divide men's and women's tasks separately.

Hanna Wass

docent of general political science

university of Helsinki

The level crossing boom lowers with electric control. Picture: Hanna Pihlajamäki

How do the level crossing booms work?

Metsäkalteva school's 2A class students, Hyvinkää

Level crossings the booms are automatically controlled.

This happens in two ways. At some level crossings, the system conducts a small, harmless electric current to the rails. When the train is close enough, an electric current starts to flow along the train's axis from one rail to another, causing the system to lower the booms.

At other level crossings, a device that lowers the wheels of the train has been placed on the track before the level crossing. The device counts the total number of wheels on the train.

The first wheels passing over the device start the descent of the booms. When the same number of bikes exceeds the counter on the other side of the level crossing, the booms go up.

The warning systems are activated at least 30 seconds before the arrival of the train. That is, when the white light of the level crossing turns red, the booms lower and the warning sound blares, the train is already really close and you can no longer cross the track.

There are also many level crossings in Finland that do not have booms, lights or clocks.

Level crossings must always be crossed with caution. Slow down, look left, right and left. And if there is no train coming and the booms are not down, cross the track quickly.

Vesa Ruohomäki

project manager, track safety equipment

The Finnish Railways Agency

Astronauts Naoko Yamazaki (left) and Soichi Noguchi prepare a Japanese meal on the International Space Station in 2010. Picture: NASA TV/Reuters

Does food spoil in space?

Teppo Jokinen, 5

Usually food spoilage is caused by an excessive amount of germs, i.e. bacteria. When food is stored in the cold, bacteria usually cannot multiply. Therefore, perishable food is stored in the refrigerator or freezer.

Conditions on the International Space Station (ISS) are considered favorable for space pilots. In this case, bacteria can also live and spoil the food. There are no refrigerators or freezers for food at the station.

Astronauts often eat picnic food that can be kept at room temperature for a long time.

Outside the station, in space, the liquid evaporates easily, causing the objects containing the liquid to dry out. Namely, there is no air pressure in space that would hold solid matter together better.

If, for some reason, a space pilot were to throw, for example, a bun outside the station, the bread would dry to a crumb and then crumble. The bacteria in the crumbs would die of dryness. Then the bread would not spoil.

Minna Palmroth

professor of space physics

university of Helsinki

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