87993
Get Daily General Knowledge Questions and Answers Feedback and ads: @askme_feedbackbot
How classification system of all matter and life was viewed in the European middle ages?
Medieval thinkers of Europe took account of organisms’ classification on a philosophical and theological basis.
The classification systems used then were Aristotelian systems, including the Scala Naturae (the Great Chain of Being/Existence), a nature ladder used to order organisms in one unit.
The concept of the Great chain of being/existence was viewed by medieval thinkers of Europe, e.g. by Thomas Aquinas (1225-1274), as an immutable order given by God.
In the hierarchy of the Great chain of existence, God is at the top, above the angels. Angels, like God, are wholly spirits, have no physical body, and are therefore immutable. Underneath is man, composed of both spirit and matter. They are not permanent in nature as they change and disappear. Below are animals and plants. At the bottom is the mineral matter of the earth itself.
Subscribe- t.me/askmenow
How scientists are classifying life?
✅ It is taxonomy that is essential to classify living organisms into different groups and subgroups.
✅ In simple words, the definition of taxonomy is a branch of science that deals primarily with the description, identification, nomenclature, and classification of organisms.
✅ The term “taxonomy” was developed from two Greek words, “taxis,” meaning arrangement, and “nomia,” meaning distribution or method.
✅ There are in fact different definitions of taxonomy, and based on them, taxonomy is considered a sub-branch of systematics or a synonym of the latter term. It is also thought that biological nomenclature is either a part of taxonomy or a unit of systematics.
ℹ️ Systematics is the consideration to identify the taxonomy of organisms and their nomenclature, classification based on their natural relatedness, and the analysis of variation and evolution among the taxa.
Subscribe- t.me/askmenow
What is meant by orbital resonance?
Two celestial bodies are in orbital resonance if their orbital periods can be expressed as a ratio of two integers.
It is caused by the changing gravitational forces of bodies which go round each other.
Orbits are usually ellipses, not circular, and as a satellite goes round a planet or two stars go round each other, the gravitational forces can change, sometimes hugely. Also, the planets and stars are usually not spherical. They spin, and vary in their degree of oblateness. This also changes the forces on an orbiting body.
For example, two planets, both orbiting a parent star, are said to be in a 2️⃣:1️⃣ resonance when one of the planets takes approximately twice as long to orbit the star as the other planet ⬆️.
In our own Solar System, Neptune and Pluto are in resonance (in this case 3️⃣:2️⃣), as are many moons of Saturn and Jupiter.
ℹ️ The area of mechanics, which is used for these studies, is called celestial mechanics.
Subscribe- t.me/askmenow
Who sleep better: women or men?
💤 In a new study, researchers unveiled insights into the sleep health of middle-aged and older adults in Canada 🇨🇦, identifying social determinants that contribute to disparities in sleep satisfaction, efficiency, and duration.
❗️🚹😴🚺 The study revealed that men report sleeping better than women, and women report lower sleep satisfaction and efficiency compared to men. This disparity persisted across different sociodemographic backgrounds.
👵👨🦳 Contrary to previously held beliefs, the study found that sleep actually improves with age - older adults (aged 65 and above) reported better overall sleep health compared to people from 45 to 65 years old.
💰🏡 Socioeconomic factors like income level and homeownership also had an impact on sleep. Higher socioeconomic status also emerged as a significant predictor of better sleep health. Individuals with higher income levels, those who are retired and homeowners reported better sleep quality.
Subscribe- t.me/askmenow
How many camel species are there?
Camels are mammals with long legs, a big-lipped snout and a humped back.
There are 2️⃣ extant species of camels:
🐪
the Dromedary or Arabian Camel, Camelus dromedarius, which has a single hump, gets up to about 2 m (6.5 ft.) tall at the shoulder, has a body length of about 3 m (10 ft.) and weighs 400 to 600 kg (880 to 1,325 lbs.).
It can be found in North Africa and the Middle East, and exists today only as a domesticated animal.
🐫
the Bactrian camel, Camelus bactrianus, which has two humps, grows to a shoulder height of 1.8-2 m (6-6.5 ft.), has a body length of 3 m (10 ft.), and normally weighs 600 to 1,000 kg (1,320 to 2,200 lbs.) when fully grown.
It lives in Central Asia.
Most Bactrians are also domesticated animals, but there are still about 1000 wild Bactrian camels in the Gobi Desert in China and Mongolia.
ℹ️ The name camel comes to English via the Greek κάμηλος (kámēlos) from the Hebrew gamal or Arabic Jamal.
Subscribe- t.me/askmenow
Can artificial materials become magnetic?
🧲The most commonly known forms of magnetism are ferromagnetism (the spins of all the electrons in a material point in the same direction) and its weaker version – paramagnetism (the electron spins point in random directions).
🧲Exploring properties of moiré materials (experimental materials made by stacking two-dimensional sheets of molybdenum diselenide and tungsten disulfide with a lattice structure containing electrons) scientists discovered a new form of magnetism.
🧲Initially the material exhibited paramagnetism, but as researchers added more electrons to the lattice, it showed a shift, becoming ferromagnetic.
❗️The existence of this alternate “kinetic magnetism” has been theoretically predicted for decades but not previously observed in solid materials.
🌡For this experiment, the material had to be cooled down to a fraction above absolute zero, and the phenomenon will be investigated more closely at higher temperatures.
Subscribe- t.me/askmenow
What is the brain’s surprising reaction to “all-nighters”?
Most people who have pulled an all-nighter are familiar with that “tired and wired” feeling. Although the body is physically exhausted, the brain feels slap-happy, loopy and almost giddy.
The exact mechanisms in the brain that lead to these effects have remained poorly understood.
In a new study, researchers induced mild, acute sleep deprivation in mice and then examined their behaviors and brain activity. Not only did dopamine release increase during the acute sleep loss period, synaptic plasticity also was enhanced - literally rewiring the brain to maintain the bubbly mood for the next few days.
While researchers do not fully understand why acute sleep deprivation is somehow activating to an organism, they suspect evolution is at play.
This discovery provides insights into the mechanisms of fast-acting antidepressants and may guide future drug development.
Subscribe- t.me/askmenow
How many Types of Symmetry in Biology?
✍️ Symmetry in biology refers to the correspondence of body parts, in size, shape, and relative position, on opposite sides of a dividing line or distributed around a central point or axis.
There are 3️⃣ main types of symmetry in animals ⬆️
✅ Spherical, rare in animals and found mainly in Protozoa (e.g., Volvox, Heliozoa, and Radiolaria) and in eggs and early embryos of some animals.
✅ Radial, found in some sponges (Sycon), Coelenterates (Hydra, jellyfish), echinoderms (e.g.,starfish).
✅ Bilateral, found in many invertebrates, e.g., annelids arthropods, etc., and all vertebrates. It is strongly associated with cephalization.
Scientists also distinguish
✔️ Biradial Symmetry, found in organisms with morphological features (internal or external) of both bilateral and radial symmetry. e.g, sea anemones.
☘️🌱🌸🌻 Plants exhibit often both radial symmetry and bilateral symmetry, which has a lot to do with pollination strategy.
Subscribe- t.me/askmenow
Why temperature anomalies are so important?
📌A temperature anomaly is the difference from an average, or baseline, temperature.
📌The baseline temperature is typically computed by averaging 30 or more years of temperature data.
📌Anomalies are measured by the number of degrees that the temperature varies from the average and can be:
➕positive (the observed temperature is warmer than the baseline)
and
➖negative (the observed temperature is cooler than the baseline)
📌The anomalies are due to land-ocean-atmosphere processes that dynamically determine the weather and climate.
📌Anomalies are used to measure global surface temperature instead of absolute temperature because:
✔️absolute estimates are challenging to obtain and are uncertain
✔️anomalies describe how climate is changing over larger areas and over time more clearly.
❗️The world has been showing a frightening abundance of positive anomalies in the past decade, which means the world is getting warmer.
Subscribe- t.me/askmenow
What is at the heart of the SI standard?
The SI is defined in terms of a set of 7️⃣ defining constants:
1️⃣the caesium hyperfine frequency
2️⃣the speed of light in vacuum
3️⃣the Planck constant
4️⃣the elementary charge
5️⃣the Boltzmann constant
6️⃣the Avogadro constant
7️⃣the luminous efficacy of a defined visible radiation
The complete system of units can be derived from the fixed values of these defining constants, expressed in the units of the SI.
The 7️⃣ base units are:
1️⃣Second (s), unit of time
2️⃣Meter (m), unit of length
3️⃣Kilogram (kg), unit of mass
4️⃣Ampere (A), unit of electric current
5️⃣Kelvin (K), unit of thermodynamic temperature
6️⃣Mole (mol), unit of an amount of substance
7️⃣Candela (cd), unit of luminous intensity
The SI standard also includes units that are derived from the base units and are defined as products of powers of the base units. For example, one derived unit is the newton, which can be expressed in terms of base units as 1 kg m/s2.
Subscribe- t.me/askmenow
How does feeling lonely relate to spending time alone?
ℹ️ Loneliness - the subjective experience of social isolation - is a common experience that can become an enduring feature of everyday life.
Researchers have discerned the nuanced relationship between feeling lonely and actually being alone. The study involved over 400 participants with archival data collected in a series of studies completed over the last 20 years.
Key facts:
✔️ Loneliness becomes pronounced when individuals spend more than three-quarters of their time alone.
✔️ In older adults (above 67 years), the correlation between loneliness and time spent alone is particularly strong, with a 25% overlap.
✔️ In younger people, aloneness and loneliness are just two different things. Young persons may feel lonely in a crowd, or they may not feel lonely when they are by themselves.
To better quantify social behavior, the research team is developing a smartwatch app akin to fitness trackers.
Subscribe- t.me/askmenow
How many pets are in the world?
✍️According to different sources, there are over 1 billion pets in the world.
🇺🇸🇨🇳🇪🇺The USA, China and the EU alone, there are more than 500 mln 🐱 and 🐶.
Besides cats and dogs, the world pet population also includes animals like reptiles, fish, birds, rabbits, livestock, horses, hamsters, guinea pigs, mice, ferrets, iguanas, snakes, etc.
🐹After dogs and cats, hamsters are popular pets.
🇧🇷🥇Brazil ranks first in having the most small 🐶 per capita on the globe. In terms of exotic pets, it has the most unique number of animal pet species in the world.
🇷🇺🏆59% of Russian households have pet cats, making it the country with the highest overall share of cat owners.
🇬🇧🐢🐍🐊The highest pet reptile concentration - 1.45 mln reptiles - is in the United Kingdom.
🇮🇹🥇Italy takes first place in ornamental pet 🦜 in the world with 12.88 mln in households.
🇹🇷🥈Turkey takes second place with 11.2 mln ornamental birds in households.
Subscribe- t.me/askmenow
What were the first currencies?
💰 When, where and why money originated is uncertain and complicated. Because ancient civilizations developed at different times and recorded their history with a range of different approaches, archaeologists and historians can only make best guesses.
🐚🌾💎 Both shell money (comprised of shells or beads) and commodity money (comprised of objects that have a practical use, like grain) appear to have made up early forms of currency all around the world, from the Indigenous tribes of America to the villages of Africa to the populations of Asia and the South Pacific islands. Other objects likely used as early forms of currency vary immensely, from bricks of tea and livestock to gems and metal fragments.
ℹ️For example, shells ⬆️ were used as currency in ancient China and, about 5,000 years ago, Mesopotamians developed a banking system where people could "deposit" grains, livestock and other valuables for safekeeping or trade.
Subscribe- t.me/askmenow
What are some hydrogen bonding examples and applications?
I. Some examples of hydrogen bonding are as follows.
☑️ Ammonia
The hydrogen bonds in ammonia (NH3) are formed between nitrogen and hydrogen atoms. Nitrogen is a highly electronegative atom that is linked to hydrogen atoms in order to make hydrogen bonds.
☑️ Hydrogen Fluoride
❗️ Fluorine is an element that has the highest value of electronegativity, and it forms the strongest hydrogen bond.
☑️ Alcohols
Alcohols are organic compounds. It contains at least one -OH group. When any molecule containing the hydrogen atom is connected to either oxygen or nitrogen directly, it usually has the tendency to form hydrogen bonding.
☑️ Carboxylic Acid
Hydrogen bonding can occur in a pure carboxylic acid in between two molecules of acid in order to produce a dimer. The hydrogen bonding in carboxylic acid doubles the size of the molecule.
II. Some of the applications and effects of hydrogen bonds are given below.
🟢 Hydrogen Bonds in Plants
Water has the property to stick to itself (cohesion) and also with other molecules (adhesion). When water droplets fall on a leaf, the hydrogen bonds present between the molecules of water are more substantial than the intermolecular forces of adhesion between the water molecules and the leaf. The high surface tension of water is explained by this property.
⚪️ Hydrogen Bonds in Proteins
Intramolecular hydrogen bonding is responsible for different types of proteins such as secondary proteins, tertiary proteins, and quaternary proteins and as well as for the structure of the nucleic acids.
🧬 Hydrogen Bonds in DNA (Deoxyribonucleic Acid)
The double-helix model of DNA consists of two intertwined strands held together by a base pair. The hydrogen bonding present between the bases on adjacent strands is responsible for this. Because of different structure bases, adenine (A) always forms hydrogen bonds with thymine (T). Guanine (G) always forms hydrogen bonds with cytosine (C) in contrast.
Subscribe- t.me/askmenow
What is a new ultra-strong chemical bond lately discovered by scientists?
❗️Scientists have recently discovered a totally new type of chemical bond.
⚪️↔️⚪️ In the new study, the researchers dissolved a hydrogen-fluoride compound in water, and watched how the hydrogen and fluorine atoms interacted. What they found was a hydrogen bond with the strength of a covalent bond, binding atoms together into something resembling a molecule.
ℹ️ The new bonds had a strength of 45.8 kilocalories per mol (a unit of chemical bonding energy), greater than some covalent bonds. E.g., in nitrogen molecules two nitrogen atoms are bound together with a strength of about 40 kcal/mol. A hydrogen bond typically has an energy of about 1-3 kcal/mol, an ionic bond - between 5 and 10 kcal/mol.
✍️ According to scientists, this hybrid covalent-hydrogen bond not only challenges our current understanding of what a chemical bond exactly is, but also offers the opportunity to better understand chemical reactions.
Subscribe- t.me/askmenow
Who were ancient taxonomists?
ℹ️Taxonomists are researchers/biologists who analyze the relationship among organisms and aggregate them into groups.
Examples of earlier taxonomy are shown on ancient Egypt’s walls about medicinal plants by early Egyptian taxonomists ⬆️.
Aristotle (384-322 BC)⬆️, ancient Greek polymath, was able to classify organisms for the first time and then grouped them into two major categories, i.e., plants and animals. Several groups of animals proposed by him, such as Anhaima, Enhaima, sharks, and cetaceans, are still used to this day. Anhaima includes animals with no blood (now referred to as invertebrates), and Enhaima - animals with blood (vertebrates).
Theophrastus (371-287 BC)⬆️ was Aristotle’s student and is often called the “Father of Botany”. He continued the classification process and mentioned 500 plants and their uses in his book, Historia Plantarum. Some plant groups, such as Cornus, Crocus, and Narcissus, can be traced back to his findings.
Subscribe- t.me/askmenow
Why are orbital resonances important for science?
Orbital resonances are the source of both stability and chaos, depending sensitively upon parameters and initial conditions.
Orbitally resonant systems are extremely important to find because they tell astronomers about the formation and subsequent evolution of the planetary system.
Planets around stars tend to form in resonance but can easily have their orbits thrown around, e.g. after a close encounter with a passing star.
As a result, only one percent of all the multi-planet systems stay in resonance, according to researchers.
🔭That’s why astronomers observe planetary systems around stars that are believed to harbour planets in resonance.
⬆️ Such a rare star system with 6️⃣ exoplanets has been recently discovered with an architecture unchanged for billions of years. This star, HD110067, lies 100 light-years away in the northern constellation of Coma Berenices, is the brightest known system with 4️⃣ or more planets.
Subscribe- t.me/askmenow
Why do women need more sleep than men?
According to a study, men need 7-8 hours of sleep where women need 8-10 hours that leads to different circadian rhythms and to more sleep for women.
The sleep cycles are similar, but cortisol goes down and melatonin goes up sooner in women than men.
The interaction between circadian phase and time asleep was significant for sleep efficiency, in that the circadian disruption of sleep became stronger as sleep progressed.
While a person sleeps, their hormone levels are being replenished, and when a woman is deprived of sleep it can mess with cycles that take place within the female body that don’t happen for men.
Another study found that for women, poor sleep is strongly associated with psychological distress, and greater feelings of hostility, depression and anger. In contrast, these feelings were not associated with the same degree of sleep disruption in men.
ℹ️ As per studies, women require about 20 minutes more sleep than men.
Subscribe- t.me/askmenow
Do you know these amazing facts about camels?
✍️ Old-World species of camels (genus Camelus) are part of the Camelidae family, which include two other South American genera with two species each, Lama (llama, guanaco) and Vicugna (alpaca, vicuña). While nowadays there are no camelids in North America, scientists suppose that all members of the Camelidae family originated in North America.
✍️ In addition to their humps, camels have other ways to adapt to their environment. They have a third, clear eyelid and two rows of long lashes that protect their eyes from blowing sand. They can also shut their nostrils during sand storms.
✍️💧 Camels can survive a 40 percent weight loss and then can drink 113 liters (30 gallons) of water in just 13 minutes. Their bodies rehydrate faster than any other mammal.
✍️🩸 Camels have oval-shaped red blood cells that help continue blood flow during times when water is scarce, and a special type of antibodies lacking the light chain, besides the normal antibodies found in other species.
✍️🌡 Though many people think that camels only live in hot climates, they do well in temperature ranges from minus 29 degrees C (20 degrees F) to 49 degrees C (120 degrees F).
✍️ Humans first domesticated camels between 3,500–3,000 years ago. It is thought that the Bactrian camel was domesticated independently from the Dromedary sometime before 2500 B.C.E. and the Dromedary between 4000 B.C.E. and 2000 B.C.E.
✍️🇷🇺Wild Bactrian camels (Camelus ferus) were discovered in 1878 by Nikolai Prejevalsky, a Russian geographer who explored Mongolia and Tibet.
✍️🧬 For many years, the wild Bactrian (Camelus ferus) was thought to be a subspecies of the domestic Bactrian. However, in recent years, DNA analysis confirmed that Camelus ferus was a separate species with three more chromosome pairs than the domestic Bactrian.
✍️🇦🇺 A substantial feral population (originally domesticated but now living wild) estimated at up to 700,000 lives in central parts of Australia.
✍️ Camels can run at 40 kph (25 mph) for long periods. They have a natural pacing gait, moving both legs from the same side of the body at the same time.
✍️ Camels are known for spitting on people. In fact, the animals are throwing up the contents of their stomach along with spit. This is a defense tactic when the animals feel threatened.
✍️🎦 Camels make a rumbling growl that was one of the noises used to create Chewbacca's voice in the "Star Wars" movies.
Subscribe- t.me/askmenow
What is the world’s largest “current” iceberg?
☑️ The iceberg, named A23a, is the world's largest iceberg for a moment.
☑️ It is about 400 meters (1,312 feet) thick, and almost 4,000 square kilometers (1,544 square miles) in area.
☑️ A23a broke off from the Antarctic coastline in 1986 and became grounded in the Weddell Sea, and is now on the move for the first time in 37 years, according to recent satellite images ⬆️.
☑️ It is unclear why the iceberg is suddenly on the move again after 37 years, but scientists believe that it has probably shrunk enough in size to lose its grip on the seafloor as part of the natural growth cycle of the ice shelf.
ℹ️ A23a has held the “largest current iceberg” title several times since the 1980s, occasionally being surpassed by larger but shorter-lived icebergs, including A68 (around 175 km long, 50 km wide, 5,800 sq.km in area) in 2017 and A76 (around 170 km in length, 25 km wide and 4,320 sq.km in area) in 2021.
Subscribe- t.me/askmenow
What gives unique sensory properties to animals?
Cryptochromes (CRYs) are a structurally conserved but functionally diverse family of proteins that can confer unique sensory properties to organisms.
They are:
▫️found in a variety of organisms
▫️often involved in light-controlled biological processes
▫️responsible for circadian rhythms.
🪱E.g., the marine bristle worm Platynereis dumerilii ⬆️, employs a special Cry protein designated L-Cry to distinguish between sunlight and moonlight as well as between different moon phases. This is essential for the worms to synchronize their reproduction to the full moon phase via an inner monthly calendar, also called circalunar clock.
🐤In migratory birds, researchers tried to learn more about an unusual eye protein called CRY4, which is part of a class of cryptochromes. Scientists found that birds have evolved a mechanism that enhances their ability to respond to light, which can enable them to sense and respond to magnetic fields ⬆️.
Subscribe- t.me/askmenow
Where is the head on a starfish?
For centuries, naturalists have puzzled over what might constitute the head of a sea star, commonly called a "starfish."
Sea stars begin life as larvae with a bilateral body plan, but instead of displaying bilateral symmetry, adult sea stars—and related echinoderms, such as sea urchins and sea cucumbers—have a five-fold axis of symmetry without a clear head or tail ⬆️
In a new study, researchers used a variety of high-tech molecular and genomic techniques to understand where different genes were expressed during the development and growth of sea stars ⬆️
The “head” of a starfish, the researchers found, is not in any one place. Instead, the headlike regions are distributed with some in the center of the sea star as well as in the center of each limb of its body. No part of the sea star ectoderm expresses a “trunk” genetic patterning program, suggesting that sea stars are mostly headlike.
Subscribe- t.me/askmenow
What are some interesting temperature highlights of October 2023?
According to climatologists,
🌡 🗓 October 2023 was the warmest October on record globally, with an average surface air temperature of 15.30°C, 0.85°C above the 1991-2020 average for October and 0.40°C above the previous warmest October, in 2019.
🌡🌏 The global temperature anomaly for October 2023 was the second highest across all months in the ERA5 dataset, behind September 2023.
🌡🌊 The average sea surface temperature for October over 60°S–60°N was 20.79°C, the highest on record for October.
🌡 The month as a whole was 1.7°C warmer than an estimate of the October average for 1850-1900, the designated pre-industrial reference period.
ℹ️ ERA5 is the latest climate reanalysis produced by European researchers. All the reported findings are based on computer-generated analyses, using billions of measurements from satellites, ships, aircraft and weather stations around the world.
Subscribe- t.me/askmenow
What tells us how much heat the object has?
🌡Temperature tells us the degree of hotness or coldness of an object.
🌡It is a measurable physical property like other measurable physical properties such as velocity, mass, and density.
🔬At a microscopic level, temperature describes the average kinetic energy of molecules within a material or system.
🌡Temperature is typically seen in units of degrees Celsius or °C (in some countries the Fahrenheit scale is used).
🌡Celsius is the standard unit of temperature in the metric system of units. Celsius is split up into degrees, with one degree being 1/100 of the temperature difference between the boiling and freezing points of water.
🌡Fahrenheit is equal to 9/5 degrees Celsius.
🌡Scientists use the Kelvin scale, which doesn’t measure temperature in degrees. Zero Kelvin is ‘absolute zero’, the coldest temperature and lowest energy level equal to about -273 degrees °C.
🌡A thermometer is a device used for measuring temperature.
Subscribe- t.me/askmenow
What is the International System of Units (SI)?
✍️ The International System of Units is a global standard for expressing the magnitudes or quantities of important natural phenomena.
📌 Also referred to as the Metric system, the System of Units is commonly abbreviated as SI, which comes from the original French name, Système international d'unités.
📌 The SI standard builds on an earlier system of measurement called the meter-kilogram-second (MKS) system.
📌 The Bureau international des poids et mesures (BIPM) ⬆️ is responsible for promoting and describing the SI standard. Known as the International Bureau of Weights and Measures in English, the organization was established in 1875 and operates under the supervision of the International Committee for Weights and Measures (CIPM).
ℹ️ The International Treaty of the Meter was signed in Paris on May 20, 1875 by seventeen countries and is now celebrated around the globe as World Metrology Day.
Subscribe- t.me/askmenow
How does the ‘Spanish Dancer Galaxy’ look like?
🔭🌀This vibrant and dynamic-looking image ⬆️, recently released by the ESA, features the spiral galaxy NGC 1566, which is sometimes informally referred to as the ‘Spanish Dancer Galaxy’.
💃🏻The galaxy owes its nickname to the vivid and dramatic swirling lines of its spiral arms, which could evoke the shapes and colours of a dancer’s moving form.
🌌NGC 1566 lies around 60 million light-years from Earth in the constellation Dorado, and is also a member of the Dorado galaxy group.
ℹ️In spite of more sophisticated observation techniques, it is rather challenging to pin down members of groups such as the Dorado group. When working out members of a galaxy group, astronomers are not necessarily equipped with the knowledge of the size of the individual galaxies, and so have to work out whether galaxies really are relatively close together in space, or whether some of them are actually much closer or much further away.
Subscribe- t.me/askmenow
What were the first coins?
The oldest known uses of coins as currency can be traced back to many archaic civilizations.
🪙 The Lydian stater ⬆️ is often considered the first minted — or state-produced — coin, issued by King Alyattes in the 7th century B.C. in a Greek kingdom of Lydia, located in modern-day Turkey.
These Lydian coins were made of electrum, a naturally occurring gold and silver alloy, and were supposed to conform to a specific standard of weight.
They weren’t very uniform compared to modern coins. Minted in the Lydian capital of Sardis, the coins generally featured a lion (known as the Lydian Lion) and bull facing each other.
🪙 Even before the Lydian stater, coins could be minted in ancient China.
According to scientists, clay molds ⬆️, discovered in a bronze foundry at Guanzhuang, in China’s Henan Province, were likely used as a mint for making standardized coins around 640 B.C. - the approximate birth year of Lydia’s King Alyattes.
Subscribe- t.me/askmenow
Why does paper tear more easily when it's wet?
📍The answer comes down to the paper's chemical structure.
📍At the heart of it, paper is just cellulose fibers — natural polymer molecules from wood — woven around each other to form a sheet. Within a normal sheet of paper, these fibers are interlocked with each other through little hook-like irregularities on the individual strands of cellulose and also bonded between each other by hydrogen bonds.
📍When you tear a piece of dry paper, you just need to overcome all the intermolecular forces, the friction, and the fiber entanglements.
📍On a chemical level, the water disrupts the vital hydrogen bonds. Because water contains oxygen-hydrogen bond, it begins to form its own hydrogen bonds with the cellulose, blocking the other fibers from binding. With fewer interactions between the individual cellulose polymers, it becomes easier to separate the fibers, so less force is needed to tear the paper.
Subscribe- t.me/askmenow
How does electronegativity affect chemical bonding?
✔️Electronegativity is the ability of an atom to attract a pair of electrons in a chemical bond.
✔️The higher the electronegativity of an element, the more strongly it attracts the shared electrons.
⬆️The difference in electronegativity between two bonded elements determines what type of bond they will form.
⤴️When atoms with an electronegativity difference of greater than 2️⃣ units are joined together, the bond that is formed is an ionic bond.
⤵️When atoms with an electronegativity difference of less than 2️⃣ units are joined together, the bond that is formed is a covalent bond.
ℹ️The concept of electronegativity was introduced by Linus Pauling in 1932; on the Pauling scale, fluorine is assigned an electronegativity of 3.98, and the other elements are scaled relative to that value.
In the periodic table ⬆️ electronegativity increases from bottom to top in groups, and increases from left to right across periods.
Subscribe- t.me/askmenow
What chemical bonds are considered weak?
Covalent and ionic bonds are both typically considered strong bonds.
However, more temporary and weak bonds can also form between atoms or molecules.
2️⃣ types of weak bonds are:
📍Hydrogen bond ⬆️, an intermolecular force (IMF) that behaving a bit like a magnet forms a special type of dipole-dipole attraction when a hydrogen atom bonded to a strongly electronegative atom, exists in the vicinity of another electronegative atom with a lone pair of electrons. For example, in water molecules (H2O), hydrogen is covalently bonded to the more electronegative oxygen atom.
Individual hydrogen bonds are easily broken, but many hydrogen bonds together can be very strong.
📍 London dispersion forces ⬆️ occur between atoms or molecules of any kind, and they depend on temporary imbalances in electron distribution.
ℹ️ These weak bonds are both often defined by a general term of van der Waals forces.
Subscribe- t.me/askmenow