Why do people with dark skin color have light palms and feet? Detailed answer

BIG ENCYCLOPEDIA FOR CHILDREN AND ADULTS
Free library / Directory / Big encyclopedia for children and adults

Why do people with dark skin color have light palms and feet? Detailed answer

Big encyclopedia for children and adults

Directory / Big encyclopedia. Questions for quiz and self-education

Did you know?

Why do people with dark skin color have light palms and feet?

The main factor that determines the color of human skin is the concentration of melanin pigment, which is fixed at the genetic level. Regardless of the basic color of the body, the skin on the palms and feet of all people is light, as it does not contain melanin.

Authors: Jimmy Wales, Larry Sanger

Random interesting fact from the Great Encyclopedia:

Who was the first to use cryptography for correspondence?

The earliest documented use of cryptography for correspondence took place in Sparta around 400 BC. For secret correspondence between military leaders, the Spartans used the Scytala cipher device. It consisted of two cylinders of the same diameter. Each of the corresponding parties had one of these cylinders.

Encryption was carried out as follows: a narrow strip (tape) of parchment was wound (spirally) around the cylinder, and then the text that needed to be encrypted was written out on the tape along (along the generatrix) of the cylinder. After winding the tape, it was sent to the correspondent. He, wrapping tape around his top hat, read the message. It was assumed that the secrecy of correspondence is ensured by keeping the diameter of the cylinders secret. Instead of special cylinders, rods, spears, handles of swords, daggers, and so on were used.

The Athenians found a simple method for deciphering texts recorded using Scitala (the authorship of this method is attributed to Aristotle). It was enough to wrap a strip of intercepted parchment around a fairly long cone at its base, and then gradually move it to the top of the cone. Where the diameter of the cone coincided with the diameter of the "Scitala", the letters on the parchment were combined into syllables and words.

Test your knowledge! Did you know...

▪ Who is Joseph Lister?

▪ What part of a capsicum is the hottest?

▪ Which city is represented in sign language by two pistols pointing at each other?

See other articles Section Big encyclopedia. Questions for quiz and self-education.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Machine for thinning flowers in gardens 02.05.2024

In modern agriculture, technological progress is developing aimed at increasing the efficiency of plant care processes. The innovative Florix flower thinning machine was presented in Italy, designed to optimize the harvesting stage. This tool is equipped with mobile arms, allowing it to be easily adapted to the needs of the garden. The operator can adjust the speed of the thin wires by controlling them from the tractor cab using a joystick. This approach significantly increases the efficiency of the flower thinning process, providing the possibility of individual adjustment to the specific conditions of the garden, as well as the variety and type of fruit grown in it. After testing the Florix machine for two years on various types of fruit, the results were very encouraging. Farmers such as Filiberto Montanari, who has used a Florix machine for several years, have reported a significant reduction in the time and labor required to thin flowers. ... >>

Advanced Infrared Microscope 02.05.2024

Microscopes play an important role in scientific research, allowing scientists to delve into structures and processes invisible to the eye. However, various microscopy methods have their limitations, and among them was the limitation of resolution when using the infrared range. But the latest achievements of Japanese researchers from the University of Tokyo open up new prospects for studying the microworld. Scientists from the University of Tokyo have unveiled a new microscope that will revolutionize the capabilities of infrared microscopy. This advanced instrument allows you to see the internal structures of living bacteria with amazing clarity on the nanometer scale. Typically, mid-infrared microscopes are limited by low resolution, but the latest development from Japanese researchers overcomes these limitations. According to scientists, the developed microscope allows creating images with a resolution of up to 120 nanometers, which is 30 times higher than the resolution of traditional microscopes. ... >>

Air trap for insects 01.05.2024

Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>

Random news from the Archive

Philips Hue Secure series cameras and sensors 07.09.2023

The Philips Hue Secure series expands with new products, including smart cameras and sensors.

The Philips Hue Secure range now includes a master camera, a battery-powered wireless camera, a camera with a flashlight and contact sensors.

All cameras are capable of recording 1080p video and have night vision and motion detection capabilities. They also support two-way communication, allowing you to interact with visitors at the door.

The Philips Hue Secure range also includes contact sensors that can be placed on doors and windows to monitor their status (open/closed). Sensors can be used to set alarms and automate other smart devices.

The launch of new devices on the market is scheduled for autumn 2023. The wired camera will be available for $200 or $230 with a desktop mount. The battery powered camera will cost $250 and the camera with flashlight will cost $350. Contact sensors are available for $40 for one or $70 for two.

Other interesting news:

▪ New V9 series micro switch

▪ The impact of energy-saving lamps on nature

▪ Revolutionary water desalination method

▪ Found a substance that restores damaged muscles

▪ Electric explosion of aluminum foil will effectively bond the metal

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ site section Digital technology. Article selection

▪ article Little victorious war. Popular expression

▪ article Why do watches need stones? Detailed answer

▪ article Marshmallow officinalis. Legends, cultivation, methods of application

▪ article The principle of operation of the metal detector. Encyclopedia of radio electronics and electrical engineering

▪ article Electrical installations in fire hazardous areas. Electrical apparatus and devices. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages of this page

Home page | Library | Articles | Website map | Site Reviews