Children’s science questions also consider mosquito hunger, the coolness of the water, and the color of cyanobacteria. And is an electric car safe in thunderstorms?
Anna Romppanen, 13
Annan described headache bothers when you quickly eat something really cold especially in warm weather.
The pain often lasts less than a minute, often just a few tens of seconds. By nature, the pain is whistling and severe. However, it is also harmless. In English, the phenomenon is called brain freeze, which refers to brain freezing.
The phenomenon is due to a change in blood flow to the palate of the mouth caused by a cold food or drink. The cold initially causes the blood vessels to constrict on the palate, to which the body responds quickly by dilating the blood vessels.
Increased blood circulation tends to heat cold food or drink. The rapid change in blood flow is sensed as pain after activation of facial pain receptors. Information travels to the brain, especially through the branches of the so-called trigeminal nerve.
According to some studies, people with migraines have a greater tendency to get cold-induced headache conditions. They can be prevented by consuming a cold food or drink more slowly so that the blood circulation in the palate has time to warm it up better.
Specialist in Neurology, University Researcher
Helsinki University Hospital
When a mosquito meets a human, it starts sucking blood, i.e. is the mosquito always hungry?
Nanna Hämäläinen, 9
We we often only notice a mosquito when it comes and try to suck blood. However, in mosquito life, such situations are rather short moments.
When mosquitoes hatch, they flock and mate first. The female then embarks on a flight. It needs to find a good source of protein for egg development. For exercise, it needs carbohydrates and fat for nutrition.
The female’s most common meal is flower nectar, but it can also eat ripe and rotting fruit, aphid honeydew, and sometimes even insect larvae.
Only a few plants have so much protein in their honey that a female can lay eggs. Some females in the northern regions may have larval protein stores that they can utilize for laying. However, the best option is blood from humans and other vertebrates.
So the female does not inject the man for food, but for reproduction. Blood is a bad alternative to a mosquito as a food because it is low in fat and hardly carbohydrates. Only when the hibernating mosquito is activated in the middle of winter does it sometimes have to settle only for blood because no other food is available.
So a mosquito is not always hungry. In fact, it doesn’t even know it needs food. The activity of a mosquito in different situations is strongly controlled by the genes it inherits.
Docent of Applied Zoology
university of Helsinki
Why does the water get cold even though the water is warmer than the air, for example 27 degrees?
Veika Kalevi Koistinen, 7
Man cools about 2 to 5 times faster in cold water than in air of the same temperature. This is because heat is removed from the body faster in water than in air. In other words, the thermal conductivity of water is clearly higher than that of air.
When the body loses heat, it warms the environment near the skin. In water, water heated by the body is always replaced by colder water. There is an insulating layer of air around the earth that slows the escape of body heat.
The temperature of water where the body does not cool or heat, but is in thermal equilibrium, is about 35 degrees. The corresponding figure for air is about 27 degrees. Thus, a water temperature lower than 35 degrees cools a person. However, the 27-degree water is so warm that the body doesn’t cool down very quickly, at least if you swim or play actively.
Children usually cool their bodies faster than adults. In children, thermoregulation is still developing and the small size of the body also speeds up cooling. In addition, heat-producing muscle tremors are not as active in children as in adults.
senior researcher, docent
National Institute of Occupational Health
Is it safe to be lightning in electric cars?
Ella Luoto, 12
Electric car is as safe in thunder as a more traditional internal combustion engine car. The cars have a metal body, ie the basic structure that carries the car.
If lightning strikes a car, an electric current flows along the body first invisibly and then most often jumps through the tire as an arc to the ground.
This does not allow the flash to get inside the car, so the person is quite safe. Also, all Electrical technology installed inside the body is well protected.
Cars must comply with regulations on so-called electromagnetic compatibility. During the tests, the car is exposed to all kinds of disturbances and must not be damaged.
So the cars have also been tested for a strong lightning current of tens of thousands of amperes.
Why is cyanobacteria called cyanobacteria, even though it is usually green?
Alma Lanki, 8
In good condition indeed, cyanobacteria are mostly green or yellowish green in color. When they die, however, they stain water, beaches, and even ice turquoise bluish or blue. Bluish blue-green algae deposits are commonly observed on beaches, especially in the fall.
A bluish color is caused by a dye called phycocyanin released from decomposing cyanobacteria. That color is typical of cyanobacteria. The name cyanobacteria is thus based on the color caused by phycocyanin.
The algae of the group of green algae, on the other hand, are bright green in color. That color is caused by dyes called a- and b-chlorophyll.
Green algae belong to algae, but cyanobacteria are bacteria. Therefore, cyanobacteria are also called cyanobacteria or cyanobacteria. The name cyanobacteria is used because their functions are similar to those of microscopic small phytoplankton algae.
Blue-green algae connect or convert carbon dioxide and water into sugar and oxygen for use by other organisms using solar radiation energy.
Finnish Environment Institute
Send the question, the full name and age of the questioner to firstname.lastname@example.org. The column will be edited by Touko Kauppinen and Juha Merimaa.