Science questions for kids | Why do people sometimes talk in their sleep?

Eino Hokkanen, 10

In dreams speaking involves the activation of language areas located in the cerebral cortex. It often happens in one way or another during exciting dreams.

Often, the longest talking in dreams takes place during the rem, or blink time, when we see the most dreams in general. However, the exact reason for talking in dreams is not yet known.

Most often, talking in dreams is normal behavior or is triggered by momentary stress. The reason why some people talk more often in their sleep than others is largely explained by hereditary reasons.

Frequent sleep talking can also sometimes be caused by a behavior disorder related to REM sleep, but it mainly occurs in men over 60 years old. It can be treated with medication.

Probably almost all people have talked in their dreams at some point, because more than half of people know that they have done so at some point. It is very common in children and young people: one in five often talks in their sleep.

Things spoken during sleep are short, typically only 1–5 words long.

Liisa Kuula

PhD in psychology

university of Helsinki

Can you cry if you haven’t had a drink in a long time?

Snow Kalela, 9

If the body does not get enough water through food and drink, it starts to dry out. Dehydration is harmful because water is important for the functioning of the body’s cells. If the cells dry out, the body does not function normally.

Water is also generally needed to regulate the functioning of the body. It is necessary, for example, for moistening mucous membranes such as the mouth, maintaining temperature through sweating, transporting nutrients and removing harmful waste products.

When there is a lack of water, the body starts to conserve it, and does not produce as much water-containing secretions as pee, saliva and tears. If you haven’t drunk enough in a long time, you can cry, but there will be fewer tears. In the end, their income may even stop altogether! If there are not enough tears, the eyes dry out and become painful and red.

Under normal conditions, the body can survive without water for approximately three days before more serious symptoms start to appear. It happens faster in a hot environment or when straining the body.

A child should get about 1.5 liters of water daily, an adult a little less. If the severe lack of water continues for a very long time, it eventually leads to life-threatening symptoms such as coma or kidney failure.

Severe dehydration does not occur unnoticed or suddenly. The body monitors the fluid balance and informs the need for water well in advance with a feeling of thirst. A good rule of thumb is to drink when you’re thirsty.

Mikael Segerstråle

university lecturer of physiology and neuroscience

university of Helsinki

What happens to a mosquito if it sucks blood from a person who has applied sunscreen? Will its stomach become pee?

Leo Azzari Peltoniemi, 4

Dog mosquitoes during their lifetime they drink only the water of flowers. Females of many mosquito species also drink water for food, but several also suck blood.

Blood proteins are of significant benefit to mosquitoes. Thanks to the proteins, there are more offspring and they are in good shape. All warm-blooded animals, such as moose, cattle, reindeer and humans, are important blood sources for mosquitoes.

Sun cream is applied to the surface of people’s skin. Female mosquitoes find blood under the skin, so fat is unlikely to affect them in any way.

Some of the ingredients in sunscreen may be absorbed into the human bloodstream, but the concentrations are so low that it hardly harms mosquitoes.

If the mosquitoes get access to the sunscreen in some other way, it will not attract them. Mosquitoes don’t have stomach problems at all. It is helped by the fact that their diet does not vary.

Reima Leinonen

an entomologist

Ely center in Kainuu

Which are more important, pollinators or bacteria?

Edith Hultman, 8

Bacteria are tiny organisms that have conquered almost all places on Earth that are favorable for life.

Pollinators, on the other hand, are mainly insects, but also, for example, some birds and bats act as pollinators.

Both bacteria and pollinators are a very important part of nature’s diversity and the food web between species.

Humans and other animals would not get along without pollinators and bacteria. A huge number of bacteria live on our skin and inside us, which help us. They participate, for example, in breaking down the food we eat, without which the digestion of food would not be successful.

Cyanobacteria, on the other hand, produce the oxygen necessary for life through contact.

Of course, there are also bacteria that cause diseases in humans and other animals. We have to fight against them constantly.

Pollinators, on the other hand, pollinate a large part of the plants and thus ensure the reproduction of the plants.

Plants produce oxygen through contact and are food for animals, among other things. Without pollinators, our dinner table would be missing, for example, berries, fruits and rapeseed oil.

In the end, it’s impossible to say whether bacteria or pollinators are more important. Both groups of organisms ensure the flourishing of life on Earth.

Ilari E. Sääksjärvi

professor of biodiversity research

University of Turku

Why do tangerines have white spots on their surface?

Into Kivekäs, 4

White softening on the surface of a peeled tangerine is called mesocarp and albedo. The mesocarp protects the juicy parts of the fruit from drying out and damage.

The function of the fruit is to protect the seeds inside it and help them spread to new places of growth.

It is important for a mandarin to have an attractive appearance and smell, so that some animal would eat it and thus carry the seeds in its intestines further away from the mother plant. When the animal excretes the seeds into nature, they can grow into a new plant and more fruit.

Most of the mesocarp comes off when you peel the fruit, but some remains in place. Mesocarp tastes bitter, but it is not dangerous to eat. It contains, for example, healthy dietary fibers and vitamin C.

The mesocarp of tangerines and other citrus plants is also used in baking and cooking.

Sanna Gunell

PhD in molecular plant biology

University of Turku

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