The summary is made by artificial intelligence and checked by a human.
The electricity discharged from the trams is caused by a fault in the contact between the pantograph and the catenary wire.
The blue-ringed cod uses its strong venom for both predation and defense.
Hummingbirds and dragonflies can fly in place like helicopters.
The word socket can be a root of the corresponding German word.
Electricity is sometimes visibly discharged from trams between the contact wire and the trolley. What causes this?
Mauno Judin, 4
Electric is transferred to the tram when the metal pantograph located on top of the trolley and the copper contact wire above it collide. Sometimes between the contact wire and the pantograph you can actually see sparking or even a small flash, which is called an arc.
Those light phenomena are created if the pantograph momentarily loses its contact with the driving wire. In this case, electricity continues to flow through the air.
The phenomenon is the result of a voltage difference between two different electrical points. Lightning is about a very similar phenomenon. In Helsinki, for example, the overhead wire has a voltage of 600 volts, so touching it would be life-threatening.
Sparking or burning can occur especially in winter, when a thin layer of ice may accumulate on the driving wire.
Driving past the so-called section separator, i.e. the point that divides the flow of electricity in the contact wire, may also cause the same thing. The light phenomenon is not dangerous because it happens at such a height. Sometimes on a dark night it can even be a great light show.
Hannu Stam
infrastructure service manager
Urban Transport Ltd
The coloring of blue-ringed cod warns predators.
Why are some species as poisonous as they are? For example, the poison of the blue-ringed cod is actually many times stronger than cyanide
Vilhelmina Blomberg, 9
Monet species are able to use poison if necessary. In addition to animals, toxins are also secreted by, for example, several species of plants and fungi.
The poisons of organisms are often strong. It is convenient because it means that the poison does not have to be used in large quantities often.
Among other things, strong venoms help venomous snakes quickly paralyze prey such as birds and small mammals. In this case, the prey lurks close, so the snake can find it easily.
The blue-ringed cod mentioned by Vilhelmiina is also among the most poisonous animals in the world. It preys especially on crustaceans such as crabs and shrimps.
Strong poisons often also help effectively in defense. A long fight with both enemy and prey could be dangerous. For example, the blue-ringed cod uses the nerve poison it secretes both to paralyze its prey and, if necessary, also to defend itself with it.
Blue-ringed cod, poison dart frogs and many other poisonous species also often use their colors to warn enemies. Enemies often dodge the poisonous creature from a distance.
However, poisonous organisms do not always use poisons, even when defending themselves, because producing them is tiring for the body. For example, venomous snakes may only bite as a warning when defending themselves, but may not inject venom into the wound.
Ilari E. Sääksjärvi
professor of biodiversity research
University of Turku
Dragonflies can fly like a helicopter.
Does anything in nature fly like a helicopter?
Albin Sovasto, 10
If helicopter flight means that the animal can fly in place, sideways and even backwards, the answer is yes. For example, flower flies, dragonflies, hoverflies and hummingbirds do this.
Some larger birds, such as the kestrel and the osprey, are also able to hover in place for a while, but they are unable to fly sideways and backwards.
In addition to the main rotor, helicopters have a tail rotor, i.e. two rotating structures suitable for flying. If the question means whether any animal has developed similar structures, the answer is no. For example, dragonflies and gliders use two pairs of wings for their flight, and hummingbirds and flies use one.
Hummingbirds are capable of helicopter-like flight because the downswing and elevator muscles of their wings are equally strong. In general, in birds, the retractor muscle is clearly stronger than the levator muscle. Hummingbirds also take a more upright position in a helicopter-like flight than in a cruising flight, and the wings then make a propeller-like movement in the horizontal plane.
Dragonflies, flies, hoverflies and many other insects are light animals capable of helicopter-like flight without even changing their position.
That Hohtola
Emeritus Professor of Animal Physiology
University of Oulu
The Finnish word socket is similar in structure to the German word Steckdose.
Why is a socket called a socket?
Lassi Haatainen, 3
A lot socket includes the idea that the tips of the plug are inserted into the housing. A plug is also called a plug or plug.
Normally, the word box brings to mind boxes such as a chocolate box or a matchbox, but in the field of technology, a box has the meaning of a protective case.
The developers of electrical engineering vocabulary have been able to take terms from other languages when inventing a model. The word socket is similar to the German compound word Steckdose. The German word is made up of words meaning to inject and can or box.
Socket is an established word for which it is not easy to come up with a new word that better describes the object in question.
Leena Joki
dictionary editor
Center for domestic languages
Send the question, the questioner’s full name and age to [email protected]. The column is provided by Touko Kauppinen.
Correction October 25 at 7:45 AM: Fixed caption. In the picture, a dragonfly is flying, not a hummingbird.