Why?

WHY are clams used as live sensors? The water supply systems in Warsaw and some other Polish cities use clams as live sensors. They are connected to water that needs to enter the city's water supply, and if it contains any contaminants such as heavy metals or pesticides, the clam shells close. The computer system monitors this thanks to the coils and magnets installed on the flaps and automatically shuts off the water supply until specialists can conduct the necessary tests.

WHY can some fish be treated as hermaphrodites? For instance, gubans and parrotfish can change from females to males. From the eggs of these fish, mostly females hatch. They mature, lay eggs one or more times, and then turn into males. Ladies generally do not like to grow old, so in the case of these fish species, nature meets them halfway. Young fish are mostly females; experienced fish are males. In clownfish families, there is a strict hierarchy. The female becomes the largest individual, followed by the male and juveniles. One coral polyp can live only one dominant pair. The female bites the male by the fins, reminding him who the master of the house, and the parents together mushtet young. If the female dies, the male gets a "higher social status" and becomes the female. The role of the male begins to be played by the largest of the remaining "in the house" juveniles. Thus, in one lifetime, many reef fish manage to try themselves in two hypostasis at once.

WHY should we sleep in the dark? Here is a tiny organ, about one gram in weight, located in the center of the brain. Despite its small size, it plays a huge role in the body, regulating many of its vital functions. For example, when dark, it produces serotonin, a substance called the pleasure hormone, or the happiness hormone. Melatonin is also produced only at night. This hormone normalizes blood pressure and glucose levels, one of the body's main sources of energy. Only in total darkness does the brain produce hormones, the supply of which helps us function normally during the day.

WHY is the watch worn on the left hand? In 1904 Cartier's friend, the aviator Alberto Santos-Dumont, asked Cartier to make a watch for flying. Cartier invented the Santos, the first wristwatch for men (mechanical). The Santos was an extremely wearable wristwatch. During the First World War the wristwatch replaced the pocket watch and became popular among officers. The Santos wristwatch appeared as a tool to be worn on the left hand, as most people were more handy with their right arm than with their left. When working, the main actions are performed with the right hand. To avoid damage, the watch was worn on the left hand. Besides, a wristwatch had to be wound and the crown was on the right hand.

WHY shouldn't alcohol be used to keep warm? Alcohol affects the vascular center of the brain, causing blood vessels throughout the body and head to dilate. This creates a deceptive sensation of warmth, while in fact the temperature of the human body decreases, mainly due to heat transfer to the environment. First of all, alcohol promotes expansion of peripheral capillaries and vessels, creating a feeling of a rush of heat, thereby reducing the vigilance of citizens, as cold and frost they are no longer afraid of. This insidious property of alcohol can significantly harm you on a frosty day. Drinking alcohol and stepping out into the cold, you can get very hypothermia and get sick, since the body is forced to consume more heat than in a sober state. Moreover, the stronger the alcoholic beverage, the stronger and faster comes this feeling of pseudo warmth and relaxation, which is soon replaced by chills.

WHY do dogs twist in one place before lying down? Lots of dog owners notice that their pets twist in one place before they go to sleep. Experts say that such a strange and somewhat funny ritual is most likely related to the habits of their canine ancestors, who lived in the wild. A full turn in one place is the animal's subconscious way of mowing down grass and leaves to get a sort of nest to sleep in. The wild ancestors of domestic dogs slept outdoors, so they weren't always warm and safe. If you tuck grass, leaves, or snow in, you get a much cozier and more comfortable place to sleep. Perhaps the dog makes a circle before going to sleep to feel safer. Sometimes you may also notice the dog starting to make "digging motions." In extreme heat, it is simply necessary to dig a small hole that is cooler to escape from overheating. In cold weather, a hole can also protect.

WHY is the power of machines measured in horsepower? Since the first steam engine was invented, it was necessary to determine its cost-effectiveness as a replacement for horses, and therefore how much money to pay for the machine. Some work was performed with a steam engine, then with horses, finding how many horses could do the same work - so we got power in horsepower. The short term power of a horse is much more than 1 hp, the long term power of 1 hp can provide not every horse (it was beneficial to the buyer of the steam engine, so the horses were selected hardy enough). Later on hp was abandoned as not related to other physical quantities directly, without coefficients, but for figurativeness and by inertia of thinking, technical devices, the power of which a person must directly feel (car, airplane, ship) left for use the expression of capacity in horsepower.

WHY are planets, satellites, and stars round while asteroids are not? Small asteroids have too weak gravity to deform rocks, so objects up to a few hundred kilometers in size have an irregular shape. The matter of a star or planet tends to be at the same distance from its own center of gravity. The reason here is the same as why the water in a pond is set at the same level, rather than rising with a hump.

WHY do cats wallow in dust? Wild cats, forced to find their own food, had to constantly worry about camouflage. Their prey, small rodents, wields a good sense of smell, thanks to which they can detect the approach of the hunter. Rolling on the ground, the cat tries to blunt the vigilance of its potential prey by minimizing its own scent and masking it with the smell of plant pollen and mineral particles contained in dust. Although a domesticated cat no longer needs a disguise, instinct makes the animal behave as its ancestors did when they hunted game in ancient Egypt or Africa. But we cannot rule out the possibility that whenever your pet defiantly rolls down on its back, showing its adorable tummy, it does it solely to attract attention. It is a peculiar request of your pet to give her a few minutes, to caress her, to play with her.

WHY don't we remember being born? A group of scientists believes that the loss of infant memories is related to the active process of new cell formation-neurogenesis. According to Paul Frankland, recent research has proven that neurogenesis can both shape and erase information about the past. We don't remember the first years of life due to the fact that this is the most active period of neurogenesis. Then neurons begin to reproduce at a slower rate and cannot process some of the childhood memories.