Who was Nettie Stevens?

Nettie Stevens was an American geneticist who discovered that sex is determined by chromosome.

Nettie Maria Stevens was born on July 7, 1861, in Cavendish, Vermont. The family moved to Westford, Massachusetts, after her mother's death. In 1896, she joined the then newly established Stanford University earning her under graduation and post graduation degrees there. She received a Ph.D. in cytology (the study of structure and function of cells) from Bryn Mawr College in 1903. Her Ph.D advisor was the geneticist Thomas Hunt Morgan.

In 1904, Nettie was offered a research assistantship position at Carnegie to investigate the topic of heredity and sex determination. Thanks to Gregor Mendel, by 1900, rules of heredity were known to the scientific community. It was well established by then that parental traits pass to offspring and that the offspring inherits an equal number of chromosomes from each of its parents. But scientists did not know what determined the sex of the offspring.

By studying the cell division in the male common mealworm, Nettie identified a large chromosome and a small chromosome - we now call these X and Y. She concluded that a particular combination of the chromosomes X and Y

was responsible for the determination of the sex of an individual an individual that inherits XX will be female and XY will be male this was evidence that a physical characteristic-in this case the sex of an individual - is linked to differences in chromosomes.

Edmund Beecher Wilson of Columbia University Americas first cell biologist independently made the same discovery as Nettie, later in 1908. Bat Thomas Hint Morgan has been credited with the discovery of sex chromosomes because of his related work on white mutant gene of fruit flies and was even awarded a Nobel Prize in 1933 for the same. Nettie was neither recognized immediately after her discovery, nor invited to speak on theories on sex determination while Morgan and Wilson were. Experts attribute this to gender discrimination Nettie remained an associate in experimental morphology from 1905 until her death in 1912 date to cancer. Nettie Stevens discovered two new species of single-celled organisms: Lionophora macfarlandi and Boveria subcylindrica. She also documented their life cycles.

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Can you roll an empty soda can without touching it or kicking it or blowing on it?

What you need:

An empty soda can. A PVC pipe, A towel

What to do:

1. Place the can on the floor or on a big table on its side.

 2. Rub the length of the pipe with the towel. Hover it close to the can and start moving it horizontally, parallel to the ground.

What happens:

The can rolls with the motion of the pipe! You can roll it back and forth without even prodding it!

Why?

The answer is static electricity Static means stationary. When you nub two objects against each other (like the pipe and the towel), they develop stationary electrical charges. To understand why this happens, we have to go to the microscopic level. Everything in our world is made up of tiny particles called 'atoms. These atoms are, in turn, made up of even smaller particles known as electrons, protons and neutrons. The protons and neutrons remain inside the atom but the electrons like to use any excuse to jump in and out of the atom. When you rub two objects together, the electrons from one object jump to the other. This exchange of electrons is what is termed as electrical charge. Electrical charges attract or repel each other depending on their kind. If two objects have same electrical charges, these charges repel each other. Opposite charges, on the other hand, attract. The can and the pipe seem to have opposing charges on them. So wherever the pipe moves, the can follows.

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Paper planes are passé. Let’s make a new kind of glider

What you need:

A drinking straw, card paper or any stiff paper, tape, scissors

What to do:

1. Cut the paper into three strips. Each strip should measure 1 inch (2.5 cm) by 5 inches (13 cm).

2. Take two of the strips and tape them together in the shape of a hoop. Make sure that both their overlapping ends are at least an inch long so that the hoop stays in shape after being taped.

3. Make another smaller hoop with the last strip of paper making sure to overlap its ends a bit more as well.

4. Tape the hoops to either end of the straw, with the straw on the inside of the hoops, at their base.

5. Now, try tossing the whole thing into the air, like you would a paper plane. The smaller hoop should be in front and angled slightly upwards.

What happens:

With a little practice, you can make your hoop glider fly further than any paper plane! Time for that race with friends!

Why?

The two hoops help keep your straw lifted and balanced in the air. The larger hoop helps to create 'drag' or air resistance. This is a sort of friction force that air exerts on moving objects to oppose their motion. Thus if an object is flying fast, it experiences more drag as the air tries to slow it down. But although the speed is reduced due to drag, the force also makes sure that your glider doesn't just whizz to the ground and instead glides slowly through the air. The smaller hoop in front acts like the nose of the glider and makes sure that it doesn't veer off-course. Also, remember that under the influence of gravity two objects. irrespective of their weights generally fall downwards at the same speed That means if you throw a feather and an iron ball from the third floor of a building, they will reach the ground together (of course other factors such as air drag need to be eliminated or reduced to observe this). So despite your two hoops being heavier than the straw, the entire thing travels together and reaches the ground together too!

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Pressure cookers can not only cook stuff but also shrink it.

What you need:

A Styrofoam glass, a pressure cooker, a gas stove, a metal grate. a heatproof plastic bowl, water, timer

What to do:

1. Cover the bottom of the pressure cooker with about 2 to 3 cm of water.

2. Place the metal grate in the water then place the bowl on the grate.

3. Keep the Styrofoam glass upright in the middle of the bow

l 4. Close the lid of the pressure cooker and place it on the stove.

 5. When the whistle of the cooker begins to hiss, start your timer.

6. For ten minutes, let the cooker do its job. When the time is up, take the cooker off the stove and place it under a cold water tap. This helps to release the pressure immediately.

7. Once the cooker has cooled, open it and take out the glass.

What happens:

The Styrofoam glass has shrunk to less than half its size!

Why?

The glass is made of Styrofoam which is the brand name for expanded polystyrene. It comprises long chains of molecules known as 'polymers that have been inflated with a gas. That is why Styrofoam feels so light. If you look at the glass carefully, you'll even see that it contains air pockets.

A pressure cooker works by turning water into vapour. Some of this vapour escapes from the whistle opening in the lid of the cooker, but most of it remains inside the cooker. This hot vapour is what creates the pressure inside the cooker. In our case, the pressure of the water vapour squeezes the air right out of the Styrofoam, causing it to shrink. That's how you get the little glass.

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If you've ever been confused between lemons and limes, you're not alone. But here's something that can help you differentiate between them better.

What you need:

A lemon (lemons are usually bigger and oval and yellow-skinned), a lime (limes are usually smaller and round and green-skinned) (Make sure the lemon and lime you use for this experiment are of roughly the same size), a knife, water, a jar

What to do:

1. Fill the jar with water

 2. Drop the lemon and the lime into the water. What do you see?

3. Next, peel the lemon and the lime using the knife. Now drop both the peels into the water.

What happens:

When both fruits still have their peels you can see that the lemon floats on water, while the lime usually sinks The lemon rind is thicker and more porous than the lime's, which could be the reason for the lemon floating (thanks to those air pockets in its skin). So, you remove the peels of both fruits and drop them into water. You will find that the lemon rind floats and the lime's doesn't!

Why?

The floating of the lemon and the sinking of the time is something that has perplexed the scientific community for a long time.

The most straightforward explanation researchers could come up with is the density (which means the number of particles or molecules squeezed together in a small space) of the lime close to the density of water but just slightly higher than it. That makes the lime just a tad heavier than the water and it sinks On the other hand, the density of the lemon is also very close the density of the water, but it is just slightly less. So the lemon can float.

Incidentally, the rind of the lime (separated from the flesh) also sinks in water, while that of the lemon floats!

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Chandrayaan-2 completes 9,000 orbits around Moon

The Chandrayaan-2, the second lunar exploration mission after Chandrayaan-1 that has been developed by the Indian Space Research Organisation (ISRO), has been in orbit around the moon for over two years now. During a Lunar Science Workshop that was held early in September 2021, ISRO chairman K Sivan stated that the spacecraft has completed over 9.000 orbits around the moon

Launched on July 22 2019, the Chandrayaan-2 mission consisted of a lunar orbiter, along with the Vikram lander and the Pragyan lunar rover. Having reached the moon's orbit on August 20 2019, it then positioned itself for Vikram's landing.

Landing failure

The landing, scheduled for September 6 2019, however, turned out to be a failure. Even though Vikram was on track and performed as expected till, kilometres away from the lunar surface, it then lost communications with the ground stations and had a hard landing on the moon. The landing failure thus meant that the Vikram lander and the Pragyan rovers were a failure. Even though the landing phase of the Chandrayaan-2 mission was a failure, the orbiter continued to go around the moon. This means that the eight instruments onboard have been able to study the moon, both using remote sensing and in-situ techniques.

Chromium and manganese

One of the most important findings from these observations for over two years is the presence of chromium and manganese on the moon's surface. Not only were the presence of these elements revealed, but the weight of these components as a percentage of the weight of the moon was also determined.

Apart from revealing these findings in the workshop in September 2021, it was also conveyed that raw data is continuously being made available in the public domain. Sivan made it clear that Chandrayaan-2's data is "national property" and has urged the entire scientific community of the country to put it to good use and further our knowledge of the moon.

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What is Inspiration4 mission?

On September 15, SpaceX’s first private flight launched into space successfully. Called Inspiration4, it was the first time a spacecraft circled Earth with an all-amateur crew and no professional astronauts. It's yet another milestone in the space tourism market. Earlier this year, billionaire businessmen Sir Richard Branson and Jeff Bezos went above Earth's atmosphere in their own space vehicles. (SpaceX's next private trip, early next year. will see a retired NASA astronaut escorting three wealthy businessmen to the space station for a week-long visit. The Russians are launching an actress, a film director and a Japanese tycoon to the space station in the next few months.) Want to learn more about the Inspiration4 mission? This week's Five Ws and One H will get you all the details.

What is Inpiration4?

The Inspiration4 mission w the brainchild of Jared Isaacman, the billionaire CEO of Shift4 Payments, a online payments company, who bought all four seats aboard the Dragon Capsule for an undisclosed hefty sum from SpaceX (Some reports put the price at $50 million per seat). The mission blasted off in the Falcon 9 rocket. The Dragon capsule, where the crew sat during the orbit, was modified for this flight. A huge glass done the largest ever space window was installed  to offer passengers a 360 degree view of space. The dome replaced the al mechanism used on Dragons to dock with the International Space Station (ISS)

The Dragon capsule orbited earth for three days at a high altitude of 585 km 160 km higher than the 155. The mission was commanded by lsaacman, who is also an accomplished pilot and adventurer.

What is the aim of the flight?

The trip was designed with the explicit intent to benefit St. Jude Children's Research Hospital, which treats and researches childhood cancers and other diseases. Started by an initial $100 million gift from Isaacman to St. Jude, inspirations has fundraising goal to raise $200 million through February 2022 to help accelerate rah advancements and  save more children worldwide. The mission has a commitment of more than $130 million with auction items related to the mission.

Why is the mission special?

The inspirations mission marks several historic milestones for human space exploration. It was the first  all-civilian crew to orbit earth, the first free flight Crew Dragon mission, and the first orbital human spaceflight mission that did not dock with a space station since the final Hubble mission on STS-125 in 2009.

Who are the crew members?

Joining the mission commander Jared Isaacman (38) on the trip are crew pilot Sian Proctor (51), who is a geoscientist, science communicator and artist Hayley Arceneaux (29), a childhood bone cancer survivor who works as a physician assistant where she was treated - St. Jude Children's Research Hospital in Memphis, Tennessee; and mission specialist Chris Sembroski (42), a U.S. Air Force veteran and a data engineer from North Carolina. Sian Proctor was, in fact, a finalist to become a NASA astronaut more than a decade ago.

How were the crew members selected? Isaacman donated two of the seats to St. Jude hospital. For one seat, the hospital selected Hayley Arceneaux and for the other, it conducted a raffle as part of a campaign to raise funds for the hospital. An undisclosed person from Embry-Riddle Aeronautical University ultimately won the raffle, but decided for personal reasons to give the seat to his friend, Sembroski, who was also one of 72.000 entrants in the raffle. Sian Proctor was selected by Shift4 Payments through a competition that rewarded the best business idea to make use of Shift4's commerce solutions.

What did the team do on the flight?

The crew took part in a health research initiative to increase humanity's knowledge on the impact of spaceflight on the human body. Once in orbit the crew performed carefully selected research experiments on human health and performance. The crew members' sleep, heart rate, blood and cognitive functions were analyzed during the mission in order to study how rookies react in space.

A series of tests through an app to assess changes in behavioral and cognitive performance were done. This is the same app that is currently used by astronauts in NASA-funded research studies.

Markers of immune function and inflammation were monitored. Balance and perception tests pre-flight and immediately post-flight were measured to study the sensorimotor adaptation during changes of gravity. In addition, SpaceX collaborated with investigators at Weill Cornell Medicine to perform a longitudinal, multi-omic analysis of the crew, including genome and spatial transcriptome analysis.

These samples and data will be added to a planned Biobank that will hold samples of the human, microbial, and environmental specimens that are collected before, during, and after missions and enable long-term research and health monitoring for astronauts and space travellers.

How did the crew undergo training?

Though the capsule is automated, the four Dragon riders spent six months training for the flight to cope with any emergency. It included centrifuge training, Dragon simulations, observations of other launch operations, Zero-G plane training and altitude training.

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Which was the first planet found using a telescope?

When Uranus, the seventh planet from the Sun, was discovered in 1781, it expanded the known limits of our solar system. It was also the first planet to be discovered using a telescope, as Mercury, Venus, Mars, Jupiter and Saturn were all bright enough to be easily visible to the naked eye.

In fact, because these planets had been known to people for millennia, Uranus was arguably the first planet in recorded history to have been ‘discovered’ at all.

The observations that established Uranus as something other than a regular star were made on 13 March 1781 by Sir William Herschel. He was using a state-of-the-art 2.1-m-long (7-ft) reflecting telescope with a 15.2-cm (6-in) mirror, which he made and installed at his home in Bath, UK. He realized that the point of light known in older star catalogues as "34 Tauri" was in fact something much closer.

He published his findings in a letter to the Royal Society the following month, initially reporting it as a probable comet. Later that year, Anders Johann Lexell (working in St Petersburg, Russia) and Johann Elert Bode (working in Berlin) made follow-up observations that led to the conclusion that the object was in a near-circular orbit, and therefore almost certainly a planet.

Herschel initially suggested calling the new planet Georgium Sidus (George's Star) after the British King, but unsurprisingly this was not a popular choice internationally. Most astronomers called the planet "Herschel" until 1782, when Bode suggested naming the planet after Ouranos, the Greek god of the sky. The name was quickly accepted, although the British government's Nautical Almanac insisted on referring to the planet as Georgium Sidus until 1850.

Credit : Science Museum 

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What are Fermi Bubbles?

The Fermi bubbles are two large structures in gamma-rays above and below the Galactic center.  They are associated with the microwave haze around the Galactic center discovered in the WMAP data and recently confirmed in the Planck data.  At the moment, there are several theoretical models and simulations developed to explain the shape and the energy spectrum of the bubbles.  In order to distinguish among the different models, a detailed comparison between the theory and the observations is necessary.  The main purpose of the meeting is to foster a collaboration between the scientists working on the theoretical and observational sides of the problem in order to deepen our understanding of the origin and the emission mechanisms associated with the bubbles.  The topics include: observational results related to the Galactic halo region, models and simulations designed to explain the bubbles, and related systems in other galaxies.

The bubbles may be related to the release of vast amounts of energy emitted from the supermassive black hole at the center of our Milky Way galaxy. We know that in other galaxies, supermassive black holes that ingest large amounts of matter can power high-energy jets. It's possible the Milky Way's central black hole went through such a phase in the past, producing jets responsible for the Fermi Bubbles we see today.

A completely unexpected discovery like the Fermi Bubbles is a special treat. However, scientists know that there are many more surprises waiting to be uncovered by Fermi. In the most recent catalog of sources from Fermi's Large Area Telescope, fully a third of detected source positions are not known to have a gamma-ray emitting object at that location. 

Credit : Space.com

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On an average, how long does it take to put on a spacesuit in microgravity?

Putting on a spacesuit takes 45 minutes, including the time it takes to put on the special undergarments that help keep astronauts cool. After putting on the spacesuit, to adapt to the lower pressure maintained in the suit, the astronaut must spend a little more than an hour breathing pure oxygen before going outside the pressurized module.

Initially, it may look like the most expensive item on the space suit is the Primary Life Support System. This unit, which is responsible for adjusting the oxygen and the temperature levels, contains several electronic devices. However, in terms of cost, the parts that NASA spends the most are the gloves of the astronauts. Spacesuit gloves are the main limiting factor when it comes to working in space. Astronauts usually handle from 70 to 110 tools, tethers and associated equipment for a typical spacewalk. Like an inflated balloon, the fingers of the gloves resist the effort to bend them. Astronauts must fight that pressure with every movement of their hand, which is exhausting and sometimes results in injury. Furthermore, the joints of the glove are subject to wear that can lead to life-threatening leaks. For this reason, the gloves are specially designed to aid astronauts' mobility.

In a nutshell, spacesuits are basically wearable spacecrafts and can not only keep astronauts alive, but also feed them, allow them to communicate, and even be used as a toilet.

Credit : Space Camp Turkey

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What is the significance of the name Armalcolite?

Armalcolite is a titanium-rich mineral with the chemical formula (Mg,Fe2+)Ti2O5. It was first found at Tranquility Base on the Moon in 1969 during the Apollo 11 mission, and is named for Armstrong, Aldrin and Collins, the three Apollo 11 astronauts. Together with tranquillityite and pyroxferroite, it is one of three new minerals that were discovered on the Moon. Armalcolite was later identified at various locations on Earth and has been synthesized in the laboratory

Armalcolite was originally found on the Moon, in the Sea of Tranquility at Tranquility Base, and also in the Taurus–Littrow valley and the Descartes Highlands. The largest amounts were provided by the Apollo 11 and 17 missions. It was later identified on Earth from samples of lamproite dikes and plugs taken in Smoky Butte, Garfield County, Montana, US. On the Earth, it also occurs in Germany (Nördlinger Ries impact crater in Bavaria), Greenland (Disko Island), Mexico (El Toro cinder cone, San Luis Potosí), South Africa (Jagersfontein, Bultfontein and Dutoitspan kimberlite mines), Spain (Albacete Province and Jumilla, Murcia), Ukraine (Pripyat Swell), United States (Knippa quarry, Uvalde County, Texas and Smoky Butte, Jordan, Montana) and Zimbabwe (Mwenezi District). Armalcolite was also detected in lunar meteorites, such as Dhofar 925 and 960 found in Oman.

Armalcolite is a minor mineral found in titanium-rich basalt rocks, volcanic lava and sometimes granite pegmatite, ultramafic rocks, lamproites and kimberlites. It is associated with various mixed iron-titanium oxides, graphite, analcime, diopside, ilmenite, phlogopite and rutile. It forms elongated crystals up to about 0.1–0.3 mm in length embedded in a basalt matrix. Petrographic analysis suggests that armalcolite is typically formed at low pressures and high temperatures.

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What was America's first space station called?

Before there was the International Space Station, before there was Mir, there was Skylab. Established in 1973, and remaining in orbit until 1979, this orbital space station was American's first long-duration orbital workshop, and the ancestor of all those that have followed.

Skylab was launched on May 14th, 1973 on a mission that is sometimes referred to as Skylab 1 (or SL-1). Severe damage was sustained during the launch when the station's meteoroid shield and one of the two solar panels tore off due to vibrations.

Since the station was designed to face the Sun in order to get as much power as possible, and the shield was ripped off, the station rose to a temperature of 52°C. As a result, scientists had to move the space station and effect repairs before astronauts could be dispatched to it.

The first manned mission (designated Skylab 2, or SL-2) took place on May 25th, 1973, atop a Saturn IB and involved extensive repairs to the station. This mission last four weeks, and astronauts Charles Conrad, Jr., Paul J. Weitz, Joseph P. Kerwin were the crew members. During the mission, the crew conducted a number of experiments, including solar astronomy and medical studies, and three EVAs (extra-vehicular activities) were completed as well.

The second manned mission, also known as Skylab 3 (SL-3), was launched on July 28th, 1973. The crew consisted of Alan L. Bean, Jack R. Lousma, and Owen K. Garriott. The mission lasted 59 days and 11 hours, during which time the crew carried out additional repairs as well as performing scientific and medical experiments.

The third and final mission to the Skylab (Skylab 4, SL-4) was the longest, lasting 84 days and one hour. Gerald P. Carr, William R. Pogue, Edward G. Gibson were the crew, and in addition to performing various experiments, they also observed the Comet Kohoutek. The crew conducted three EVAs which lasted a total of 22 hours and 13 minutes.

Skylab was occupied a total of 171 days and orbited the Earth more than 2,476 times during the course of its service. Each Skylab mission set a record for the amount of time astronauts spent in space.

Credit : Phy.org

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In which year did Max Planck win a Nobel Prize?

Max Planck received his Nobel Prize one year later, in 1919. During the selection process in 1918, the Nobel Committee for Physics decided that none of the year's nominations met the criteria as outlined in the will of Alfred Nobel. According to the Nobel Foundation's statutes, the Nobel Prize can in such a case be reserved until the following year, and this statute was then applied. Max Planck therefore received his Nobel Prize for 1918 one year later, in 1919.

Planck’s earliest work was on the subject of thermodynamics, an interest he acquired from his studies under Kirchhoff, whom he greatly admired, and very considerably from reading R. Clausius’ publications. He published papers on entropy, on thermoelectric ity and on the theory of dilute solutions.

At the same time also the problems of radiation processes engaged his attention and he showed that these were to be considered as electromagnetic in nature. From these studies he was led to the problem of the distribution of energy in the spectrum of full radiation. Experimental observations on the wavelength distribution of the energy emitted by a black body as a function of temperature were at variance with the predictions of classical physics. Planck was able to deduce the relationship between the ener gy and the frequency of radiation. In a paper published in 1900, he announced his derivation of the relationship: this was based on the revolutionary idea that the energy emitted by a resonator could only take on discrete values or quanta. The energy for a resonator of frequency v is hv where h is a universal constant, now called Planck’s constant.

This was not only Planck’s most important work but also marked a turning point in the history of physics. The importance of the discovery, with its far-reaching effect on classical physics, was not appreciated at first. However the evidence for its validi ty gradually became overwhelming as its application accounted for many discrepancies between observed phenomena and classical theory. Among these applications and developments may be mentioned Einstein’s explanation of the photoelectric effect.

Credit : Nobel Prize

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What is the symbol of Max Planck’s constant?

Planck’s constant, (symbol h), fundamental physical constant characteristic of the mathematical formulations of quantum mechanics, which describes the behaviour of particles and waves on the atomic scale, including the particle aspect of light. 

The significance of Planck’s constant in this context is that radiation, such as light, is emitted, transmitted, and absorbed in discrete energy packets, or quanta, determined by the frequency of the radiation and the value of Planck’s constant. 

The dimension of Planck’s constant is the product of energy multiplied by time, a quantity called action. Planck’s constant is often defined, therefore, as the elementary quantum of action. 

Planck's constant was formulated as part of Max Planck's successful effort to produce a mathematical expression that accurately predicted the observed spectral distribution of thermal radiation from a closed furnace (black-body radiation). This mathematical expression is now known as Planck's law.

In the last years of the 19th century, Max Planck was investigating the problem of black-body radiation first posed by Kirchhoff some 40 years earlier. Every physical body spontaneously and continuously emits electromagnetic radiation. There was no expression or explanation for the overall shape of the observed emission spectrum.

Credit : Britannica

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What are special clouds?

Special clouds are Mammatus clouds which are actually altocumulus, cirrus, cumulonimbus or other types of clouds that have a pouch like shapes hanging out to the bottoms. In these cases, clouds may form or grow as a consequence of certain, often localized generating factors. Orographic clouds get their shape from mountains or hills that force the air to move over or around them. The lenticular clouds are shaped like lenses or almonds. They may get their shape from hilly terrain another type of orographic cloud or just the way the air is raising over a flat terrain.

When moist, warm air rises to a cooler elevation, and water condenses onto microscopic dust-like seeds, bacteria or ash. Air and seeds that updraft the clouds. Every planet with an atmosphere has clouds. That includes the moon. Clouds reflect the suns light, which causes them to appear white. Big clouds are normally made up of water droplets and have a base under 2000 meters. High altitude clouds are usually made up of ice crystals, which can also serve as seeds, and have a base somewhere between 5,500 and 14,000 meters. If those crystals take on moisture, they may become too heavy for updrafts to support, which is what causes rain. So, it makes sense that shooting those so-called seeds” to clouds should make them rain out.

Credit : e-School

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