What are the characteristics of the different types of volcanoes?

These are the characteristics of 4️⃣ types of volcanoes based on the nature of their eruption and the kind of lava they release ⬇️
🌋 Shield Volcano
Shield volcanoes are huge, gently sloped volcanoes that almost exclusively erupts basaltic lava and include some of the largest volcanoes in the world. The eruptions are not explosive; the lava oozes out from the central vent or a group of vents and spreads far, building a dome shape profile like a warrior’s shield. They can be as high as 9000 meters from the base.
Lava Type: Less viscous, quite fluid basaltic lava.
Examples: The volcanoes in the the island of Hawai’i, including Mauna Loa and Mauna Kea, the world’s largest active volcanoes, rising over 9 km above the sea floor.

🌋 Stratovolcano
Also referred to as composite cone volcanoes, it is more cone-shaped than a shield volcano and includes some of the world’s grandest mountains. It is a tall conical mountain composed of an alternating layer of lava-flow, which justifies the name composite volcano. It can have a cluster of vents, with lava breaking through walls or issuing from fissures on the sides of the mountain. The eruptions are extremely explosive and dangerous. Pressure builds in the magma chamber as gases under immense heat and pressure are dissolved within the magma. When the magma reaches the vents, the pressure is released, and the gases explode violently. These can be up to 100 to 3500 meters high.
Lava Type: Highly viscous rhyolitic lava that hardens before it can spread far (high content of silica and low iron and magnesium contents)
Examples: Mount Fuji in Japan, Cotopaxi in Ecuador, Mount Vesuvius in Italy, Mount Pinatubo and Mayon in the Philippines, Volcan de Colima in Mexico, Eyjafjallajokull in Iceland, Popocatepetl in Mexico, Arenal Volcano in Costa Rica.

🌋 Cinder Cone Volcano
Cinder Cone has a characteristic cone shape. It forms when volcanic cinder, blobs of congealed lava of basaltic composition, come out from a single vent. It has explosive eruptions caused by gas rapidly expanding and escaping from the molten lava that comes out like a fountain. The lava cools quickly and falls as cinders that build up around the vent forming a cone shape, leaving a crater at the summit. These volcanoes can be as high as 100 to 400 meters.
Lava Type: Less viscous, quite fluid basaltic lava (enriched in iron and magnesium and depleted in silica)
Examples: Cerro Negro in Nicaragua (Central America) and Parícutin in Mexico, the youngest volcano on Earth, which first developed in 1943.

🌋 Lava Dome
These are relatively small, circular mounds formed as the lava is too viscous to flow, which makes it piles over and around the vents. As the lava oozes out, its outer surface cools and hardens, then shatters, spilling loose fragments down its side. Lava domes are found within the crater or on the sides of large composite volcanoes. Their height depends on the size of the composite volcanoes they appear around.
Lava Type: Highly viscous, less fluid rhyolitic lava
Examples: Mount Merapi lava dome in Indonesia, the Soufrière Hills volcano, on the Caribbean island of Montserrat.

These are the characteristics of 3️⃣ types of volcanoes based on their frequency of eruption.
🌋 Active Volcanoes
Those that have erupted in the last 10,000 years and are expected to erupt again at any time.
Examples: Mount Etna in Italy and Mauna Loa in Hawaii.

🌋 Dormant Volcanoes
Those that have not erupted in the last 10,000 years, but are likely to erupt after remaining inactive for a long period.
Examples: Mt. Kilimanjaro in Africa and Mt. Fuji in Japan.

🌋 Extinct Volcanoes
Those that were active in the past, but have not erupted in the last 10,000 years and are not likely to erupt in the present or the future.
Examples: Mt. Kenya in Africa and Mt. Aconcagua in South America.

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What is the difference between bugs and insects?

A bug is a type of insect. All bugs are insects, but not all insects are bugs.

Here are properties shared by most bugs:
🪲 Sucking mouthparts.
🪲 Do not undergo metamorphosis.
🪲 Partially hardened or fully membranous forewings, which fold over one another (although a few bugs lack wings altogether).
🪲 Many produce sound to communicate.

Scientists know about over 4️⃣5️⃣.0️⃣0️⃣0️⃣ true bugs, e.g.:
Aphids
Assassin bugs (including kissing bugs)
Beg bugs
Boxelder bugs
Cicadas
Firebugs
Froghoppers
Leafhoppers
Mealybugs
Scale bugs
Shield bugs
Stink bugs
Treehoppers
Water bugs (including water boatmen, water scorpions, and backswimmers)
Whiteflies

Animals that are insects but not bugs:
🐜 Ants
🐞Beetles, including Lady bugs
🐝Bees
🦋Butterflies and moths
🪳Cockroaches
🪰Flies
🦗Locusts and other grasshoppers
Mantises

Animals that are arthropods but not bugs:
🕷Spiders
Mites
Ticks
Centipedes
Millipedes
🦞🦀Lobsters and crabs

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What is the oldest discovered sundial?

☀️🕛 A sundial is a device that indicates the time of day using the position of the Sun.

According to archeologists, the world’s oldest discovered sundial dates to the 13th century B.C. It was found in the Valley of the Kings, the burial place of rulers from Egypt's New Kingdom period.

The sundial is made of a flattened piece of limestone, called an ostracon, with a black semicircle divided into 12 sections drawn on top.

To bring this 3200 year old artifact to life, researchers developed a project "Ra" that showcases the sundial's functionality. ⬆️
Numerals from 6 AM to 6 PM denote the hours. View (simulation, ostracon front, ostracon back), shadow and dial (original, equinox, winter solstice, summer solstice, today, today Luxor true solar) as well as the numerals (Egyptian, Greek, Roman, eastern Arabic, Arabic) can be toggled by means of hieroglyph buttons. The astronomical modes have been calculated for a latitude of 25.5° (Luxor).

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How to make an easy sundial?

The simplest sundial uses an upright stick called a gnomon. The shadow cast by the gnomon shows the time on a sundial face.

For an easy sundial, all one really needs is a straight stick, like a dowel or a pencil, some pebbles that mark the hours, and a watch or phone so that you can match the shadow cast by the stick to the time.

One should select a sunny location, write numbers on the pebbles and place the gnomon upright into the ground.
In the Northern Hemisphere, one should slightly tilt the gnomon toward the north, and in the Southern Hemisphere – slightly slant the gnomon toward the south. To know which direction north/south is, a compass can be used, or the gnomon can be kept straight until it’s noon - at noon, the angle that gives the best shadow is north (northern hemisphere) or south (southern hemisphere).

To calibrate such horizontal sundial, sometimes a few days and a modern clock/watch are needed.

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What are some types of sundials and common misconceptions about them?

There are many versions of sundials:
☀️🕛 Horizontal Sundial
features flat dial with a gnomon mostly perpendicular to the surface. It is the most common type and is placed horizontally.

☀️🕛 Vertical Sundial
is mounted on a vertical surface like a wall. The gnomon sits at an angle to the vertical plane.

☀️🕛 Equatorial Sundial:
The dial plate aligns parallel to the Earth’s equator, and the gnomon is perpendicular to this plate.

☀️🕛 Analemmatic Sundial
is a more complex type where the gnomon is movable and placed based on the date. The hour markers form an elliptical pattern.

☀️🕛 Polar Sundial:
The dial aligns parallel to the Earth’s axis and the gnomon points directly towards the celestial pole.

Here are also 🔟 common misconceptions about sundials.
❌ Misconception: Sundials work anywhere without adjustment.
✅ Reality: Sundials require calibration for the latitude and longitude of the new location for accurate timekeeping.

❌ Misconception: Sundials show the same time as modern clocks.
✅ Reality: Sundials show solar time, which differs from standard clock time due to the equation of time and the difference between solar noon and standard noon.

❌ MIsconception: The gnomon should always be vertical.
✅ Reality: Ideally, angle the gnomon towards the celestial pole (north in the Northern Hemisphere, south in the Southern Hemisphere) at an angle equal to the local latitude.

❌ Misconception: All sundials are the same.
✅ Reality: There are many types of sundials (horizontal, vertical, equatorial, etc.), each designed for specific conditions and purposes.

❌ Misconception: Sundials are always accurate.
✅ Reality: The equation of time, seasonal variations, and even local topography affect sundials.

❌ Misconception: Sundials only work on sunny days.
✅ Reality: Some advanced types, like heliochronometers, provide rough estimates on overcast days by tracking the sun’s position through cloud cover.

❌ Misconception: Sundials were only used in ancient times.
✅ Reality: Sundials are still appreciated today for their simplicity, educational value, and as decorative garden features.

❌ Misconception: The sundial’s shadow moves uniformly throughout the day.
✅ Reality: The shadow moves at different rates due to the Earth’s tilt and orbit.

❌ Misconception: Sundials only show time.
✅ Reality: Some sundials indicate seasons, solstices, equinoxes, and even geographical latitude.

❌ Misconception: Reading a sundial is like reading a clock.
✅ Reality: Sundials take many forms, but generally their numbers are not arranged like those on an analog clock.

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Why is June 8 an important day for the world?

🌊 World Oceans Day (WOD) is observed on June 8 and celebrates the vitality and importance of the ocean for our planet.

🌊 The ocean is a huge body of saltwater that covers about 71 percent of Earth’s surface.

🌊 The ocean contains about 1.35 billion cubic km of water – about 97 percent of all the water on Earth.

🌊 The ocean produces at least 50% of the planet’s oxygen, it is home to most of earth’s biodiversity, and has considerable impact on weather, temperature, and the food supply of all Earth’s organisms.

🌐🌊 The planet has one global ocean, though people traditionally divide it into five distinct regions: the Pacific, Atlantic, Indian, Arctic and Southern oceans.

🌊 Despite its size and impact, more than 80 percent of the ocean has never been mapped and explored by humans. A far greater percentage of the surfaces of the planet Mars has been mapped and studied.

ℹ️🇺🇳🌊“Awaken New Depths” is the theme for WOD 2024.

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How did the Earth’s ocean form?

🌐🌋 According to scientists, at the down of its existence, about 4.5 billion years ago, Earth had no ocean as it was too hot for water to accumulate in liquid form.

🌐💧 Earth eventually started to cool below the boiling point of water, allowing the early ocean to form around 3.8 billion years ago.

ℹ️ There’s some debate around how water arrived on Earth in the first place.
🌋 One theory is that volcanic activity expelled water vapor and other gases from the planet’s interior, where it already existed.
☄️ Another suggests that icy comets deposited water when they crashed into the early planet.
🤔 The reality could be a combination of these theories, plus one other that involves the major collision event that is believed to have created the moon.

🤞🍀 Regardless of the ultimate explanation, the Earth’s specific location in the solar system happens to be the perfect place for water to exist in all three phases — ice, liquid and water vapor.

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Why does water expand when it freezes?

💧 On heating, liquids expand since the molecules move with greater energy overcoming the intermolecular attraction. On the contrary, liquids usually contract on cooling. But that is not the case with water.

💧 The water molecules consist of 2 atoms of hydrogen and one of oxygen, the oxygen atom side being slightly negative, while the hydrogen atoms side – slightly positive, forming hydrogen bonds. Upon freezing, the molecules set themselves in a very open arrangement that contains more space than the water in the liquid state. Hence, water expands upon freezing and becomes less dense. On the other hand, it contracts on thawing, much unlike most other liquids.

💧 Water expands approximately by about 10%.

ℹ️ Water is not the only substance that expands when it freezes, other substances are plutonium, germanium, bismuth, gallium, silicon, etc.

✍️ This phenomenon, the anomalous expansion of water, also explains why ice is floating in water.

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What do sci-fiction-pioneer Jules Verne, horror-writer H.P. Lovecraft, and the Russian space program have in common or what are some interesting facts about Point Nemo?

📍 Who Found Point Nemo?
While the oceanic point of inaccessibility has always existed, it was only just discovered in 1992, some three decades ago, thanks to modern computing and GPS technology. A Croatian-Canadian survey engineer Hrvoje Lukatela wrote a geospatial program called Hipparchus, and found Point Nemo.

📍 Point Nemo Isn’t Named After A Fish
The etymology of Point Nemo is easily confused with Disney’s well-known protagonist — fish Nemo — in the children’s show Finding Nemo. But Point Nemo was named after the famous fictional character Captain Nemo in Jules Verne’s ‘20,000 Leagues Under The Sea.’ It translates roughly to “no man” in Latin, a name that fits a place so alone in the world.

📍 Point Nemo Is A Confluence of Lifelessness
The Nemo point is an area of the deep ocean with no islands, reefs, or other land structures. Instead, the ocean floor comprises abyssal plains, trenches, and mountain ranges plagued by perpetual darkness and silence. The extreme pressure of the deep sea and cold temperatures make it uninhabitable for most life forms. Currently, only bacteria and tiny crabs have been discovered to live in the volcanic vents on the seafloor near Point Nemo.

📍 Astronauts/Cosmonauts Are The Closest People
Surprisingly, the closest people to Point Nemo are astronauts and cosmonauts on board the International Space Station (ISS) in space. At their closest, they are about 415 km (258 ml) away from the location that marks the spot.

📍 Point Nemo Is A Spacecraft Cemetery
In the 1970s, space organizations found that an extremely remote location, such as Point Nemo, is a safe “scuttling” destination for satellites and spacecraft that are deorbited for decommissioning on expiry.
It is far enough away from air and sea traffic that the spacecraft will not be disturbed, and it is located in an area of the ocean with minimal currents, so the spacecraft and its technology will not drift away.
The first spacecraft to be sent to Point Nemo was the Soviet Union’s Salyut 1 in 1971.
Since then, more than 250 spacecraft have been sent to the graveyard, including the Mir space station, the Skylab space station, and the Beagle 2 Mars lander.
When a spacecraft is sent to Point Nemo, it is deorbited before being allowed to sink to the ocean floor. This procedure is called “geological disposal,” and it ensures that the spacecraft will not pose a threat to future space missions.
The ISS will likewise be decommissioned at Point Nemo in 2028-2030.
Ultimately, Point Nemo is a unique and fascinating place, serving an important role in space exploration.

📍 Point Nemo Is The Home Of Cthulhu
Point Nemo’s location is coincidentally the home of Cthulhu, the fictional cosmic entity created by author H.P. Lovecraft in his famous fictional work — The sunken city.
Cthulhu is a massive monster that is part octopus and part dragon and wields enormous power and influence.
Point Nemo is the perfect place for Cthulhu to hide from the world.
Lovecraft puts the city in the South Pacific Ocean at 47°9′S 126°43′W, very close to Point Nemo.
The fictional submerged city was first referenced in the short story The Call of Cthulhu (1928), written 66 years before the computation and eventual mapping of Point Nemo.

📍 Point Nemo Was Once Thought To Contain Life
In 1997, scientists recorded a very loud sound originating from point Nemo, an otherwise Lifeless/deathly place. The mysterious sound traveled across the Pacific, echoing all the way.
Since then, it’s been known as the Bloop.
Scientists ran with the hypothesis that a large aquatic animal, such as a whale or a giant squid, could have caused the sound.
With Point Nemo’s proximity to H.P Lovecraft’s sunken city, conspiracy theories flew with wild abandon.
But in 2005 researchers concluded that the Bloop was simply a phenomenon caused by large icebergs calving off an ice shelf in the depth of the dark.

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