Corrosion - Definition and types

Lots of metals are seen to change their colors, textures, and densities when exposed to air and moisture for an extended period of time. The picture above shows a car that was once new and shiny, but it has been broken down and roughened by reacting with components of the atmosphere. Another picture below shows a decaying and rough looking copper pipe that has experience partial degradation. In time, both metals will all be flakes.

 This two scenarios obviously shows that there is some form of invisible chemical reaction that leads to the irreversible damage of these metals when exposed to an open environment for a long time. Such chemical process is known as corrosion.

Definition of corrosion 

Corrosion is a process involving a metal being reconverted from it refined form to a  more chemically stable form such as oxides, hydroxides or sulfides  by natural means. 

During the process of corrosion, a metal is permanently and irreversibly degraded and broken down due to chemically and/ or electrochemically reacting with it environment.

Why does corrosion happens?

Metals are often gotten from their respective ores. Before any metal can be useful to create anything, it must first be extracted and refined from it ore. This ores can exist in form of oxides, sulfides, or salt. For example, iron(III)oxide or hematite is a common ore where iron is extracted, likewise in copper(I)sulfide for copper. These ores are most stable form in which  these metals can exist, and they always tend to remain in this stable forms.  So when extracted or refined for industrial purposes, they are less stable and they will look for any possible reaction in order to revert to stability.

Corrosion happens as the refined metals attempt to revert to their more stable raw or ore form.

Factors affecting corrosion

The reaction that causes corrosion can lead a metal to go back to it oxide or sulfide state when it react with an environments that contains traces of these compounds. The following are some factors influencing the rate or corrosion.

• Position of the metal in the electrochemical cell

The more reactive metals are easily corroded because when left exposed, it will have a higher tendency to to react with other elements like oxygen to form basic oxides. So the reactivity of the metal affects the corrosion

• Air or Oxygen.

It is the most important thing for corrosion i.e. oxidation of metal. More the exposure of metal to the air, more it will corrode. Most of the metals are corroded by the oxygen bust some of them by other gases like Copper by CO2, Silver by H2S, etc. For e.g. Copper develops a green colour coating on its surface due to the presence of air , moisture and carbon dioxide forms basic green malachite Cu(OH)2.CuCO3.

• Moisture

Moisture lead to formation of coordinate complex between metal oxide and water molecules like (Fe2O3. nH2O), etc. Moisture is present in the form of Water Vapour or capillary water in soils.

• Presence of other chemicals

Sometimes metals are corroded by the action of certain other chemicals like acids and bases. 

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Why are insects attracted to light

If you've ever observed a street light at night or turn on your porch light during the dark, what you'll probably notice is some bunch of insects flying and swimming around the light source, and the  most intriguing part of it is that they just keep on making endless circles around the light. These insects often ranges from small beetles to bugs or even moths.  

So why are insects attracted to light an why do they just keep circling around and around like that. Let find out.

It a good thing to know that insects that are naturally drawn to light are know as positively phototactic. 

The difference between insects attracted to light and those that are not is a phenomenon known as phototaxis. Certain insects, such as cockroaches or earthworms, have negative phototaxis, meaning they are repelled by exposure to light. Moths, flies, and many other flying insects have positive phototaxis, meaning they are naturally attracted to it.

It turns out that there is specifically no single explanation given by scientists on this behavior though, but there are several theories that suggest possible explanations as to why insects are attracted to lights. These theories suggest that electric lights, fires, and other glowing things might confuse the natural instinct of these insects. These natural instincts can be connected to their:

- Short term protection: 

- long distance navigation

- source of food

Short term protection:

Some insects do see light as a safety signal or an emergency beacon. When in doubt about their current environment, they fly straight to the light source for safety. Light can also be seen as a sign of an unobstructed path, which is a good thing if they're trying to escape a predator, or just to get to point B. 

Long distance navigation:

One of the theories behind these behaviors of getting attracted to light is that some insects use the moon to navigate at night. These kind of insects species tend to be nocturnal and many are migratory. So in order to stay on track while travelling long distances, they want to stay at a specific angle with respect to the moon. So it obvious that these insects possibly mistake any point of light they find in the dark for the moon. This can also explains why certain insects tend to fly in wild circles around the light; once they reach the glowing objects they thinks it the moon, they keep drastically changing their angles to the light source which ends up throwing them for a loop(literally).

Source of food:

Another thing to consider is that many insects are good in detecting ultraviolet(UV) light, flowers for example do reflects UV light  attracting some flying insects like bees and butterflies. Bees use the flower nectar and pollen as source of food. So positively phototactic insects might aim for your lamp or campfire  because they instinctively  thinks it's something they want, like a source of food.

So the next time you see an insects flying into a light source, keep in mind that not even entomologist are quite sure why it doing that. Maybe with some more research, it'll be figured  out.

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8 snakes with the world's deadliest venom

Snakes are extremely dangerous species of reptiles and no doubt they appear among the most feared creatures on the planet. One significant feature about these limbless moving reptiles is their ability to eject toxic venoms from a bite. These venoms do posses  lethal threats to other organisms, thereby making the snake a very fearsome hunter in the wild. Trust me you  really don't want to mess around the snake's territory.

Out of the 3,500 snake species found on Earth, only 600 of them are actually capable of ejecting venoms from a bite. These venoms comes in different levels of lethality depending on the amount of toxin found in it. Studying about venoms is quite complex, and snake venom works differently on different creatures. Due to this, several criteria has thus been adopted when listing the most venomous snakes.  Some lists are based on how many mice or humans one bite from a snake would kill. Other lists are more interested in the number of human deaths recorded each year from the snake.  However the standard way of measuring the degree of lethality posed by a snake's venom or otherwise known as it "toxicity" is from the median lethal dose(LD50). The median lethal dose or LD50 is the dose of venom needed to kill 50%(half) the members of a group of tested animals after a specified duration. The animal mostly used for this tests are the mice. A lower LD50 is an indication of increased toxicity. 

In our list, we're going to highlight 8 of the most venomous snake species found on earth based on the median lethal dose for mice.

INLAND TAIPAN

Inland Taipan

When it comes to the amount of toxin found in a venom, the Inland Taipan is by far the most venomous snake in the world. Being nicknamed as the "fierce snake", a single bite from an Inland Taipan can deliver a maximum of 110mg of it venom, being so toxic enough to kill at least 100 adult humans or 250 thousand mice. Although being so venomous, it has less defensive disposition unlike it counterpart "the coastal Taipan" and it shy by nature. Hence very few humans have been bitten and no human death has ever been recorded from an Inland Taipan.

VENOM REVIEW

 Rating  : Extremely toxic

 dose  ejected :  44mg

Maximum dose recorded  : 110mg

Median lethal dose for mice  :  0.025mg/kg

Components of venom and envenomation

Neurotoxins, hemotoxins, myotoxins, nephrotoxins, haemorrhagin, hyaluronidase enzyme.

Envenomation can lead rise to paralysis (such as respiratory failure and pneumonia), coagulopathy(such as cerebral haemorrhage and kidney failure), and cardiac complications.

EASTERN BROWN SNAKE

Eastern brown snake

A specie of extremely venomous snake found mostly in the eastern and central Australia and New Guinea.

The eastern brown snake is considered the second most venomous snake, only behind the inland taipan based on it LD50 value in mice. A bite from an eastern brown snake can deliver enough venom, toxic enough to kill 212,000 mice or 58 humans. It responsible for about 60% of snake bite death in Australia.

VENOM RATING : Extremely toxic

Average dose of venom ejected :  5mg

Maximum dose recorded      : 67mg

Median lethal dose for mice   :  0.0365mg/kg

Components of venom and envenomation

Neurotoxins, hemotoxins.

The eastern brown snake envenomations are characterized by DIC(disseminated intravascular coagulopathy) and VICC(venom-induced consumptive coagulopathy). Both cases can lead to haemorrhage, cardiovascular depression, renal failure, paralysis, hypotension, and collapse.

Death is mostly due to cardiovascular causes like cardiac arrest or intracranial hemorrhage (bleeding within the skull).

SEA SNAKES

Sea Snakes are more numerous than terrestrial venomous snakes. So for equality sake, we'll group them into one classification.

Sea Snakes(or coral reef snakes) are extremely venomous snakes belonging to the family elapidae and are common in tropical and subtropical regions bordering the Indian and Pacific oceans. The venoms of sea snakes contains potent neurotoxins which are some of the most toxic substances in the world. They are more toxic than venoms of terrestrial snakes, including rattlesnakes, copperheads, and cobras. Molecular weights of sea snakes neurotoxins are about 6800g/mol.

The Dubios's sea snake is the most venomous of them all, having a median lethal dose of 0.044mg/kg when injected subcutaneously to mice.

Dubios's sea snake

After the Dubios's sea snake comes the yellow bellied sea snake with a subcutaneous lethal dose of 0.067mg/kg. 

Yellow bellied sea snake

The last on the sea snake category is the Horned sea snake having a subcutaneous lethal dose of 0.079mg/kg.

Horned sea snake

COASTAL TAIPAN

Coastal Taipan

The coastal taipan is the 3rd most venomous terrestrial snake in the world with a subcutaneous lethal dose of 0.99mg/kg and a recorded venom yield of 400mg. Just behind the inland taipan and the eastern brown snake with lethal doses of 0.0225mg/kg and 0.0365mg/kg respectively. The eastern brown snake may produce venom twice as toxic as that of the coastal taipan, but the coastal taipan produces up to 20 times more venon than the eastern brown snake, and it far more aggressive than the inland taipan, therefore making the coastal taipan one of the most deadliest snakes on the planet in all perspective.

Like other extremely venomous snakes, the coastal taipan is also native to the coastal regions of northern and eastern Australia and also the island of New Guinea.

MANY BANDED KRAITS

This particular snake specie is generally found in the Asian regions including the central and southern China, Taiwan, Hong Kong, and southeast Asia. They're highly noted for having black and white or black and yellow bands all through their length. Their venoms are highly toxic, containing both the pre and post-synaptic neurotoxins which usually bind to block neuromuscular transmission and inhibit the neurotransmitter release due to their specific enzymatic activities. 

VENOM REVIEW

Rating:  Highly toxic

Average yield:  4.6mg

Maximum recorded venom: 19.4mg

Median lethal dose for mice: 0.108mg/kg

Composition: presynaptic neurotoxins, post-synaptic neurotoxins.

CONGO WATER COBRA

The Congo water cobra is a semi-aquatic snake which spends much of it time in the water. It has a small geographical range, only occuring in just small portions of Western and southern democratic Republic of Congo  and some parts of Gabon and Angola. The Congo water cobra like other cobras is equally highly venomous with venom having deadly neurotoxic content. But with a subaneous lethal dose of 0.12mg/kg, the N. Christy venom is more toxic than other cobra species, even more than the Caspian cobra which was believed to hold that position. But since the N. Christy's venom is not extensively studied, many sources still regard the Caspian cobra as the most venomous cobra species.

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Top 10 deadliest animals on the planet | part-1

There are bunch of dangerous species out there, both on land, on air, and in the waters. Most of them harm other animals for foods, mating, and territorial ownership while most of them just apply their respective means of defense on other animals, which are also harmful to say.

A lot of factors contribute to how deadly an animal is, these factors can include;  size, bite force, speed, aggressiveness, weapon effectiveness, tactical skills, etc. For example, a cheetah can take advantage of it super speed to outrun and kill preys over long distances and also escape from other more powerful rivals (like the lion), and the crocodile can deploy both it stronger bite force and aggressiveness to make a firm grip on tougher preys and devour them.

Let explain three of these factors briefly:

1. Size 

The size and relative weight of an animal serves as an advantage, both in attacking other species, or defending itself from potential harm from rivals or predators. Size is always associated with strength, stamina, and intimidation. An animal having a larger size and weight is more capable of withstanding a pound for pound combat with another animal because of it ability to hold it ground. Larger species  generate influence around other species, maneuver their tactics, and crush them. Take an elephant for instance. The only predator known to attack the elephant is the lion. But it takes a full pride of lions to bring down a full grown elephant, unlike an antelope or a zebra.

2. Bite force 

 Bite force measures the amount of pressure exerted by an animals bite. A single bite from some animals can cause lots of damages to the body, including tearing the flesh apart or even breaking the bone. It all depends on the amount of pressure given by the bite. Animals with strong bite forces are also capable of making a firm and lasting grip on their victims, especially ones with a strong repellant force and impulsive abilities. Preys who are highly impulsive in motion(like the wild beast) or agile enough do often flip theirselves out and escape from the teeths of predators with a relatively weaker bite force, but that will be an impossible mission coming to predators with stronger bite force. 

3. Speed

The faster a predator can run, the lesser the chances of it prey  to escape and the deadlier it becomes to it preys. Preys with top speed, can outrun it predators and succeed in it escape mission, making it "slow" predator look less deadlier to him, but the moment it sights a faster predator, it charges to it top speed immediately. The cheetahs are known for their top speeds, which helps them to outrun and attack their preys even from a long distance.

Below is a countdown list of the 10 most deadliest animals in the world, based on the above factors and statistics.

• Black Mamba

Though species like the Inland Taipan or the king cobra are dangerous thanks to their respective venoms, the black mamaba is especially deadly due to its speed and aggression. Found in the savannas and rocky areas of southern and eastern Africa, the species (which can grow up to 14 feet long) is the fastest of all snakes, slithering at speeds of up to 12.5 miles per hour, which makes escaping one in remote areas that much more difficult. Thankfully, black mambas usually only strike when threatened—but when they do, they’ll bite repeatedly, delivering enough venom (containing neuro- and cardiotoxins) in a single bite to kill ten people. And if one doesn’t receive the correlative antivenin within 20 minutes, the bites are almost 100 percent fatal.

Some factoids :

• Black Mamba is one of the few snakes who chase humans and bite them, primarily because of its territorial nature. They acts very aggressivly (when threatened). They do not tolerate humans or any other larger specie approaching more closely than about 40 metres (130 ft).
• To make matters worse, it is one of the fastest snakes in the earth, being able to move upto 5.5 meters (18 feet) per second. In certain situations it can chase down a running human.
• Black Mamba strikes multiple times. Literally ! No mercy whatsoever.
• Black mambas are highly venomous. It is considered lethal. Two drops of its venom can kill a full grown human being in less than 20 minutes.
• Black mamba can efficiently climb trees and they hunts during day and night due to their super night visions.

(Black Mamba)

I have added this link to a youtube video of a mamba killing a lion. You will see how, even after the lion saccumbs to the mamba’s venom, mamba keeps watch, and then after returns to strike repeatedly to make sure lion king is indeed dead.

• Cape Buffalo

Cape Buffalo , which number around 900,000 and are found in sub-Saharan Africa, are a relatively mild species when left alone, preferring to travel in massive herds to graze in early morning and late afternoon hours or to gather around watering holes to stay hydrated. However, if an individual (or its calf) is threatened or wounded, they become the incarnation of their nickname: Black Death. Reportedly responsible for killing more hunters on the continent than any other creature, these behemoths, which can grow up to nearly six feet tall and weigh close to a ton, circle and stalk their prey before charging at speeds of up to 35 miles per hour. They’re even known to continue charging no matter where they’re injured, and will not hesitate to attack moving vehicles. You don’t want to mess with those horns.

Black Death

The cape buffalo is also known to charge against their top predator (the lion), in most cases, killing or severly  injuring them.

• Crocodiles

  With a recorded bite force of 5000 pounds per square inch ( enough to bite through steel), this deadly reptile still holds the title for the strongest bite force ever measured in the animal kingdom. 

The observant person will notice that mercy did not figure in the reptilian brain.

Does that crocodile care that it is killing a small impala? Does it care a mother could be grieving or a baby is snatched to death before its time?

No. Reptiles don’t care for niceties like that.

They have no mercy. They’re not built for mercy. They’re unable to conceive of mercy and you know what? They have lived for hundreds of millions of years longer than primate

• Centipede

Alright, prepare yourself for the centipede chow-fest:

Alright, you get the idea.

Y’see, while, say, a lion stalks prey, analyzes it to see if it’s dangerous or not, and then decide to go in for the kill, centipedes aren’t as complex - and that’s what makes them frightening. When they smell prey, they just barrel towards it and attack, regardless of how big or dangerous it is. They’ll attack or eat just about anything that moves. They’re not monsters - that’s just how they’re wired. They’ll investigate any foreign scent and test-bite it, too, which is why they also eat carrion and rarely fruit.

They attack using their venomous claws - these modified legs stab into the prey and inject venom while the centipede wraps its body around the animal, trying to subdue it with its legs and keep it from struggling. If you’re lucky, the venom kills you not too long after. If you’re not lucky?

The centipede just eats you while you lay there helpless, even while you’re still alive.

Being eaten by a centipede isn’t very pleasant. They pull their prey apart with their venom claws and leisurely munch on it- this can occur even while the poor animal writhes about in pain.

So yeah. If I were to be eaten by any animal, I wouldn’t choose a centipede. Not at all.

• Polar Bear

See the picture below ? It is a polar bear eating a dolphin ! They love eating dolphins — they love eating anything, as long as it contains meat and blubber. And blood.

You might think that polar bear are land mammals, but that is not entirely true — in fact, they are considered to be aquatic mammals: they are the best swimmers of all land-animal-like mammals, and can easily swim a thousand miles (!!) without going to land. They can swim for a full week without stopping.

So in the water, nothing is safe from these fuckers as well.

Take beluga. What ? YES: beluga whales. Measuring up to 5.5 meters and weighing almost two tons.

Polar bear LOVE these guys. So they spot breathing holes in the ice, and wait. Until some beluga cannot wait any longer, and tries to catch a breath.

Big mistake !

If the polar bear cannot pull them out, they jump right in and hunt under water. No problem. Beluga taste too damn good !

Do you want to talk blubber. Do you really want to talk blubber ?

Think WALRUS. Males have giant tusks, and can weigh up to 4,400 pounds. Polar bear love to invite these blubbers to a nice romantic dinner !

Blubber, blood, skin, hair — what a feast !

Sometimes that isn’t even enough. And some big fat blubbery whale (almost) dies, and strands. And you know what will happen next …

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Top 10 hardest natural substances on earth

In both material science and mineralogy, hardness refers to the property of a material which enables it to resist plastic deformation, induced either by penetration, indentation, or scratching. It is the measure of resistance to scratching or abrasion of one material to another or simply the ability of a material to resist damage.

Hardness is an important property of a material and it often determines what it can be used for. Certain substances prove harder than another when subjected to mechanical indentation or scratching. For example, materials made from ceramic can withstand high temperatures and resist non-elastic scratching than plastic materials.

Measuring hardness

There are many ways in which the hardness of a material can be measured. These tests are often empirical, based on experiments and observation rather than fundamental theory. Most of these testing process involves the material being subjected to either scratching or indentation.

 In scratching, the most common method is the used of the Mohs scale and the instrument used in measuring the absolute hardness is called the sclerometer. The higher the absolute hardness, the greater it resistance to scratching and vice versa. The mohs scale of mineral hardness is a qualitative ordinal scale, based on the ability of one sample of mineral to scratch another mineral visibly. The higher a mineral is on the mohs scale, the more resistance it is to be scratched by another mineral. In other words, minerals having a higher number on the mohs scale can visible create a non-elastic deformation on minerals lower on the mohs scale.

Below is a brief review of the top ten strongest minerals on earth, based on the mohs scale.

Top ten hardest natural substances on earth.

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10. TALC

 Talc is a type of clay mineral mined from the earth, composing of hydrated magnesium sulfate with the chemical formula .... Talc usually appears as greenish, whitish, greyish and even as a colorless rocky material. Talc is mostly used in cosmetic and personal care products, ranging from baby powders to eye shadows. The widely known talcum powder is gotten from a finely crushed  talc. Talc is also the softest mineral on the earth.

Talc has a mohs hardness of 1 and an absolute hardness of 1.

9. GYPSUM

gypsum is a naturally occurring mineral of hydrated calcium sulfate with the chemical formula .... Gypsum is mostly found in layers of sedimentary rocks and as deposits from volcanic eruptions. They are used to make fertilizers and it also serves as the main ingredient in different forms of plasters, chalks and cement.

Gypsum has a mohs hardness of 2 and an absolute hardness of 2.

8. CALCITE.

Calcite is a pure form of calcium carbonate(...) that serves as a principal constituent of other minerals such as limestone, chalk, and marble. They are found in all sedimentary, metamorphic and igneous rocks and it one of the most common mineral on the earth.

Calcite has a mohs hardness of 3 and an absolute hardness of 14.

7.FLUORITE

Fluorite or fluorspar is a naturally occurring mineral of calcium fluoride(..). It mostly unique in it variable color spectrum, existing as blue, black, purple, brown, pink, green, etc. Fluorites are formed mostly in by the hydrothermal activities of igneous rocks and limestone. 

Fluorite has a mohs hardness of 4 and an absolute hardness of 21.

6. APATITE

Apatite is a general name given to a group of phosphate minerals which possesses similar chemical composition and physical structure. They contain elements like fluorine, chlorine and hydrogen  existing as fluorapatite, chlorapatite and hydroxaptite and having a high concentration of OH, F and CL ions, respectively in their crystals. They're mostly used as fertilizers because of their high phosphorus content.

Apatite has a mohs hardness of 5 and an absolute hardness of 48.

5. FELDSPAR

Feldspar is a general name given to a large group of rock-forming silicate or tectosilicate minerals. Feldspar is the most abundant group of silicate minerals and in turn, it is also the most abundant group of minerals found in the earth's crust, making up as much as 50-60% of the earth's crust.

It possesses the chemical formular ... and just like the apatite group, feldspar minerals have very similar structures, chemical compositions, and physical properties and they can be found in igneous, metamorphic and in most sedimentary rocks.

Feldspar has a mohs hardness of 6 and an absolute hardness of 72.

4. QUARTZ

Quartz is naturally occurring mineral and a chemical compound composed of silicon and oxygen. It is the second most abundant mineral in the earth's crust(second to feldspar) and the most abundant mineral on the earth's surface.

Quartz is the the major building blocks of most igneous rocks like granite, and felsic. It is also very common in sedimentary rocks like schist and gneiss.

Quartz has a mohs hardness of 7 and an absolute hardness of 100.

3. TOPAZ

Topaz is a crystalline mineral of the silicate group,  with a chemical formula of .... Topaz is widely used as a gemstone in jewelry and other ornaments. It is the hardest mineral in the silicate group, occurring as crystal pegmatites  in silicic rocks such as granite and rhyolite.

Topaz  has a mohs hardness of 8 and an absolute hardness of 200.

2. CORUNDUM

Corundum is a very hard natural mineral composed of crystalline form of aluminium oxide with the formula ... It also contains traces of impurities of metals such as titanium, vanadium, and chromium. Corundum is a rock forming mineral found in igneous, metamorphic and sedimentary rocks.

Corundum also exist as two types of  gemstones, namely; ruby and sapphire.

Corundum has a mohs hardness of 9 and an absolute hardness of 400. 

1. DIAMOND

Diamond is crystalline mineral, composed of a pure form of the element carbon. It is the hardest natural substance ever known to man and also has the highest thermal conductivity than any other substance. 

Diamond has a mohs hardness of 10 and an absolute hardness of 1600. 

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What is a Tyndall effect

  Tyndall effect is a phenomenon which involves the scattering of light rays by particles in a colloid or a very fine suspension when the beam of light passes through them.

When beams of lights are directed at a colloid or a very fine suspension, the individual particles of the colloid or suspension will not permit the light rays to freely pass through. Instead, the rays and the particles will undergo collision, resulting in the rays  being scattered and reflected by the particles. Making the path of the light visible.

In a solution, light travels in a straight line but when it passes through a colloid or a fine suspension, it will deviate as a result of getting reflected and dispersed by the colloidal particles, making the rays to appear visible. This phenomenon is called tyndall effects. It was named after an Irish physicist John Tyndall following this discovery.

The intensity of the scattered light depends on the frequency of the light and the size of the particles. It even stated that:  "the intensity of the scatterd light is inversely proportional to the fourth power of it wavelength". Thus, it is observed that blue lights (with a shorter wavelength) is scarttered strongly than red lights (with a longer wavelength).

You might be wondering;  'why is this reaction unique anyway'? Tyndall effects is quite responsible for so many color effects in most substances both organic and inorganic. A more common example of tyndall effect is evidence by the blue color of the eye. This is caused by light getting scattered by the translucent layer of the iris.

Other examples of tyndall effects includes:

• Scattering of light by particles of milk: Milk is an example of an emulsion (a type of colloid), containing rounded particles of fats and protein. When a flashlight is directed at a glass of milk, the light rays will scatter and the path will be visible in the glass.

• The blue colors presents in smokes from a motorcycle or a car is an example of tyndall effects, where light is scattered by smoke particles.

• Scattering of lights by water droplets in fogs: When a flashlight or a headlight is directed at foggy environments, the path of the light rays from the headlight will become visible as shown in the image below.

• When sunlight finds it way in a room where lots of dust particles are suspended, the dust particles will scatter the light from the sun, forming a visible path.

• In the laboratory, tyndall effects is used to distinguish between a true solution and a colloid solution. This is because the components forming a true solution are very tiny and unable to reflect any light rays that passes through them. While in a colloid, the particles are large enough to reflects light rays, exhibiting tyndall effect.

Another phenomenon which involves the scattering of light is the rayleigh effect.

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How the cat whiskers function

 

Their whiskers help guide the cat in the dark. Many people say cats are nocturnal but, they aren’t. When something touches a cats whisker, it sends a signal to the brain telling the cat that there is something there. I have seen too many people cut a cat’s whisker off because they grew too long. Even though the whisker is made of nerves, they won’t feel pain from cutting it off, but that doesn’t mean you should cut it off because it is vital for guiding the cat. Once the cat has used it’s whiskers to guide itself around the house, they will then remember the layout of the house and won’t need to rely on whiskers to walk around in the dark. Whiskers also explain why blind cats find their way around the house so easily.

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10 wonderful facts about rainbows

Rainbows are also one of the most beautiful and amazing natural phenomena in our atmosphere. It normally occurs as a brilliant spectrum of light in the sky in shape of an arc and sometimes seen immediately after rainfall.The formation of rainbows is thus manned by complex geometry and optics relating to the reflection, refraction and dispersion of sunlight between air and water droplet. You definitely have to study a lot of things relating to general relativity, waves and optical physics in other to fully understand the formation of rainbows, that is why this post is not about the formation of rainbows but on wonderful fact you should know about rainbows.

What are rainbows?

Simply puts, rainbows are natural showcase of light spectrum in the sky caused by the reflection, refraction, and dispersion of sunlight between air and water droplet.

10 Wonderful facts you should know about rainbows

1. Rainbows are one among many other amazing natural sight in our earth's sky, including auroras, steves and the glory phenomena.

2. Rainbows are produced when sunlight passes through droplets of water,  thats why it normally occurs immediately after rainfall. So both sunlight and droplets of water should strike each other at the right time and an observer must be position at the right geometric angle to see it. That is to say that an observer cannot see a rainbow at any angle. He/she must be stationed behind the sunlight, while the rainbow appears opposite the sunlight.

3. We have up to 12 types of rainbows which have their different methods of formation. These includes: Twinned rainbow, multiple rainbow, full-cycle rainbow, monochrome rainbow, fogbow, supernumerary rainbow, rainbow under moonlight, reflected/reflection rainbow, high order rainbows.

4. Have you ever thought of being in the exact location where a rainbow is produced so as to touch it or have a closer sight? The fact is that a rainbow is not like an object or a thing that exist physically, it's a mere optical illusion that is caused by a geometric connection between sunlight and water droplets and an observer just appears to be in the right place and positioned at the right angle to see it. Thus one cannot physically approach a rainbow. Even if you seem to see it physically close to a house or a tree, another observer standing at that location will also seem to see it farther away from itself at the same distance and angle as you saw it.

5.  The shape of a rainbow is actually a full cycle not an arc (as it sometimes appears to people), but when viewing from the ground level, an observer only happen to see half of the rainbow which is formed due to the water droplets illuminated above the ground level. But even so, it possible to see a complete circle of a rainbow when viewing from an airplane which is above the ground level.

6. The colour spectrum appearing in a rainbow comes as a result of the separation of sunlight into it component wavelength. This is similar to the spectrum obtained when pointing a light source to a glass prism, we will notice that the light will separate into it component wavelength on the other side. In the case of rainbows, water droplets serves as earth's prism, separating the light waves coming from the sun into it component wavelength. 

7. A rainbow has 7 colours, and these colours include Red, Orange,yellow, green, blue, indigo, violet. 

8. Isaac newton was the first scientist that distinguish the visible colours present in a spectrum. He divided them into 7 colours which were exactly the number of colours visible to humans on a rainbow. That is to say that although the number of colours appearing on a rainbow seems to be 7, there are also much more invisible colours present in a light spectrum, but who cares, as Robert noted, color is simply a perception created by the human visual system, and as such it has no real physical meaning whatsoever.

9. In some cases, while watching a rainbow one can see another fainter form of rainbow appearing above the original one. This is called a secondary rainbow and this occur due to a double reflection inside of the water droplet. Due to angle factor, the colour order of a secondary rainbow is always in reverse with respect to the original rainbow.

10. An artificial rainbow can be made using a water sprinkler, you must be standing behind the sun while sprinkling the water high above the ground and in a very clear sky.

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