Category: Biology

A Massive 3200 Year Old Tree in a Single Picture

By Anupum Pant

If there’s one place I’d like to visit, it is the part of California where you find giant sequoia trees. The Giant forest is one such grove in the western Sierra Nevada of California. It is home to five of the ten most massive trees on the planet.

With a tree trunk measuring 36.5 feet in diameter, the Giant Sherman in the Giant forest grove, is the largest of the trees in this grove. It is 275 feet tall! (and yet there are taller trees in existence – Hyperion – again in California, which is about 379 feet tall)

While the President tree, 3200 years old, is another one of these Giant sequoia. It has seen hundred generations of humans pass by. Throughout its life it has survived a number of storms, fires, winters, earthquakes, and climate changes. And even today it grows faster than most other trees on the planet, adding one cubic meter of wood every year.

Its trunk measures around 27 feet in diameter.  In height, its topmost point measuring at 247 feet, is slightly shorter than the Giant Sherman. Still, the tree is massive. Its huge branches hold about 2 billion needles (leaves), which is more than any other tree on earth.

It is so huge that until recently it hadn’t been captured in a single photograph (excluding satellite shots and other such smart ideas). A team from National geographic magazine joined scientists to study and photograph the tree.

the president tree

Subtle Differences

By Anupum Pant

Who’d have thought that a fun website like 9gag could teach you something useful. This is an artwork that I first saw on 9gag and wanted to find where it originated from (to give the artist its full credit). I believe, I Raff I Ruse is the blog which published it first. I could be wrong, but then the apparent source itself attaches no text that could confirms anything. And then it probably went on NPR, and consequently spread all over the web.

The artwork illustrates subtle physical differences between certain kinds of animals which look very similar to the untrained eye. It’s a very simple thing to know and you should definitely know it. The whole list includes differences between:

  • Ape and Monkey
  • Frog and Toad
  • Dragonfly and Damselfly
  • Ant and Termite
  • Wasp and Bee
  • Turtle and tortoise
  • Alligator and Crocodile

The Turtle and tortoise difference was one of these seven differences which I knew for sure. Then, I can definitely tell a wasp from a bee, an ape from a monkey, and an ant from a Termite, I still wasn’t very confident about the others. I bet you also knew at least one of these differences. And I hope you didn’t know at least one because I wish you learn something from this post.

alligator vs crocodile ant vs termite ape vs monkey dragonfly vs damselfly frog vs toad turtle vs tortoise wasp vs bee

via [9gag] and [NPR]

Wiping Sparrows Resulted in 20 Million Dead People in China

By Anupum Pant

Background

Starting from the year 1958, Mao Zedong wanted to rapidly transform the People’s Republic of China from an agrarian economy to a communist society through rapid industrialization. So, he introduced a huge economic and social campaign which aimed to make this transformation possible. It was called the Giant Leap Forward. However, the campaign ended in a massive catastrophe which resulted in the death of about 10 Million people (estimates range from 18 to 45 Million deaths). Mostly because Mao decided to mess with mother nature and created a serious ecological imbalance.

One integral part of the campaign was called the four pests campaign. The aim of this campaign was to exterminate four kinds of pests identified by Mao Zedong which would have, according to him, fixed their poor grain output in China. The identified pests were – Mosquitoes, Flies, Rats and Sparrows.

The Great Sparrow Campaign

Of all, Sparrows were considered as pests because the bird species was responsible for pecking on the grains produced by hard-working peasants. That was completely unacceptable to them. The Chinese solution – Kill all birds.

This part of the four pests campaign was known as the Great sparrow campaign. To wipe off all the sparrows, masses across the country were mobilized. Some shot birds from the sky. Others just banged metal plates when they saw sparrows. Sparrows were not allowed to rest. As a result, flying sparrows fell down out of exhaustion. There were incentives according to the volume of pests people got rid of. It was brutal.

The Ecological Imbalance

The extermination of “pests” was expected to bring about a better output in grains, but it resulted in something totally opposite. Moreover, the results of this campaign were totally devastating.

As all the sparrows were being killed, there was a serious ecological imbalance. Now, there were no sparrows left to eat the quickly multiplying insects. It resulted in the rise of real pests (insects) like swarms of locusts etc. Instead of seeing a rise in the grain yeild, China saw a drastically decreased yeild.

The Great sparrow campaign ended up being  a major factor that contributed towards the Great Chinese famine in which about 20 Million people died out of starvation.

Moral: You don’t mess with mother nature.

White Sand is Mostly Parrot Fish Poop

By Anupum Pant

Walking on the sparkling white sand on a sunny beach in Hawaii, sounds wonderful, right? Who’d even think, the white sand on Hawaii beaches, which people love walking on, is actually something that is excreted by a certain kind of fish called the Parrot fish…at least most of it – about 70% of it is poop.

Now, I suppose people walking on the beach must be all grossed out. But they shouldn’t be. It isn’t too bad after all. The sand (poop) doesn’t even smell like anything bad. It looks and feels completely fine. There’s actually no reason to be grossed out.

This is how it works…

The Parrot fish spends most of its time eating sea weed and polyps which grows on coral most of the time. When it tries to puck it off, thanks to the protruded mouth of a parrot fish, it scoops off a part of coral too. The coral and sea weed mixes and gets crushed in its throat.

The sea weed and polyps eventually get digested, while the crushed coral comes out as it is. As a result, it poops out the undigested  crushed coral.

Interestingly, in the process of taking off a chunk of coral and munching it, the parrot fish does two good things.

Firstly, it helps the coral in removing all the parasites and other things growing on it. The fish is considered to be a natural cleaner of corals. Had there been no parrot fish, corals would have died.

Secondly, the parrot fish does a great service to its own beak in this process. As a result, the beaks don’t grow too much.

The parrot fish eats a lot, and each one of them can produce about 100 kg of “sand” every year. It has been confirmed by scientists that about 70% of the sand that is present on all the tropical beaches has come out of the back side of a parrot fish at some point of time.

This is what a parrot fish looks like and this is how it poops out sand…

Bonus fact: Our planet is old and fresh water is less. So, it’s valid to say that all the water molecules that are there now have passed through something really bad, and there’s a high chance that all of it has passed someone’s urinary tract at some point.

Problem Solving Plants

By Anupum Pant

Neurobiological research on plants, sounds absurd, right? Not at all. Stefano Mancuso from University of Florence, Italy has devoted years of his life studying plants and he firmly believes that plants can communicate.

He often uses bean plants to demonstrate their mystical ability to communicate and their amazing ability to sense the environment. He has grown bean plants in a number of conditions (lighting, temperature, humidity, magnetic field etc.), while recording their growth through a time-lapse camera.

In his time-lapse videos it’s fascinating to see bean plants shooting out and making movements, as a blind man would do with his hand to sense the environment. Every single time, irrespective of its distance, bean plants are able to find the support stick to wind on…

This remarkable ability of bean plants, lacking eyes or any other known sensing techniques, has stunned scientists. Since it is sped up, the video of this shoot moving up the support stick looks a lot like some reptile’s movement.

Here, watch the time-lapse, you’ll see how amazing this little marvel of nature is…

Like a bean plant, there is another plant (if you could call it that), whose movements have interested scientists. Exactly like a bean plant does, this plant comes out too, searches and always is able to find another plant to grow on. At the same time, it is quite different from the bean plant.

Cuscuta Pentagona, as scientists call it, is a true parasite. That means, it has no roots, nor can it make food on it’s own – no photosynthesis. So, for food, it relies on neighbouring plants. And every single time, like bean plant, after coming out from the ground, cuscuta parasite is able to sense the healthiest plant. It then sinks in its suckers to suck out food from the host plant. Now watch the serial killer in action, in the voice of Morgan Freeman.

A Ghost Heart

By Anupum Pant

Before I begin, I’m happy to announce that Awesci’s feed has been featured on a smartphone app, Dabblr. I covered it a couple of days back in the interviews section. If you missed it, you might want to know what Dabblr can do and why you should use it, especially if you are a student. 

At any given time, thousands of people are there on the heart transplant waiting list. Some of these people are eventually able to find a donor, while others aren’t able to. Hundreds of people who fail to find a donor, die every year. It’s a grim state, but little can be done to change it. Texas Heart Institute (THI) had a solution for this problem – use a Pig’s heart.

(There have been cases where people have survived for some time on artificial hearts too. It’s incredible how these things work.)

A pig’s heart is a lot like our own, in shape, size and function. Of course it can’t be just taken away from a pig and installed in a human. Or people from ancient times would have done it. The researchers from THI proposed this – make a ghost heart out of it first.

For making a “ghost heart”  – a kind of a structural scaffolding – they used a simple soap solution. Once they washed the pig heart in it and may be after some other processing, they had a pure protein scaffolding, stripped off of all living cells (decellularized), which could be customized and could be used to grow a custom heart for a specific human being – by using the patient’s bone-marrow stem cells. That way the new body where it would get installed won’t reject it.

In the near future, there’s a chance we could have humans with the hearts of pigs!

Alex The Genius Parrot – A Touching Tale

By Anupum Pant

Alex was a random African grey parrot that Irene Pepperberg, an animal cognition scientist, picked up from a pet store. She had a point to prove. There wasn’t anything different about this particular parrot. And yet, for 30 years, both the parrot and the researcher worked together for hours everyday and proved something no one had ever proved before.

Irene demonstrated that a “bird brained” creature was able to demonstrate excellent language, communication and intelligence. After the 30-year long experiment, Irene had clearly shown that it doesn’t take a primate sized brain to display intelligent behaviour – or the kind of behaviour we humans label as intelligent.

In fact she says, animals display extremely intelligent behaviour all the time in nature, it’s just that we humans have a different definition of the word intelligent.

Alex knew more than 100 english words, a couple of one liners, shapes and colours. More importantly, unlike what all the parrots usually do, Alex actually understood what he said. He displayed a remarkable ability to combine 2 different words from his vocabulary to say something meaningful. It wasn’t just repetition of sounds he did.

In these 30 years, Irene had become extremely attached to Alex, had started moving on to teach him more complex tasks and treated him like a child. But suddenly on September 6th, 2007 at the age of 31, Alex died. This event left a hole in the researcher’s heart. It made headlines the next day. Economist even published an obituary like they do for famous human deaths. It was indeed a huge loss for Irene, and science. Its last words were –

You be good, see you tomorrow. I love you.

Up or Down – Cats in Space

By Anupum Pant

Cat’s righting reflex

Cat_fall_150x300_6fpsThanks to the Vestibular righting reflex, animals like cats are able to land on their feet after a fall. This is great because it helps them avoid injury. In fact, it helps them avoid injuries in a very counter-intuitive manner.

In a study done in the year 1987, researchers found that cats falling from 6 storeys or less usually have greater injuries than cats falling from places higher than 6 storeys. There have been cats who have survived a fall from as high as 32 storeys. It’s so absurd, I had to mention that.

Also cats have been often found falling from high rise buildings due to a phenomenon known as the high-rise syndrome. This happens because cats mostly have a natural attraction towards high places, often get distracted by a prey and fall.

Cats In Space?

All said, there’s no doubt that cats can right themselves pretty well. But to do it, they need to have a sense of what is up and what is down. That sense, of course comes from gravity. What happens to them in micro gravity? A little kid asked me that and I had no answer. Who would have tested that, I thought.

So I checked. To my surprise, cats-in-zero-gravity-tests (simulated weightlessness) have actually been done previously by the USAF medical division and Russian cosmonaut training centre. Here’s an interesting old video of how cat’s natural reflex to right itself by spinning longitudinally fails in a simulated zero-G environment. The video also has confused pigeons flying upside down in zero-G. The whole film can be seen here.

Through experimentation it has been found that when it comes to animals in space, there are three different kinds of behaviours seen among various animals.

The first ones are the kind of animals who freeze in zero-G and wait for the weightlessness to go away. There are others, like cats and pigeons, who start moving about madly, trying to figure out which side is up. In fact, pigeons in zero-G have been seen flying upside down too. And the third ones are who stay calm and find the best way to move around.

Geckos have been seen to take on a free-falling stance in zero-G. Fish and fruit flies are some of the creatures who can deal with zero-G very well.

And if you wish to see some long slender legs before you go, here is a video of frogs in space. The video also talks about aliens entering the earth – tadpoles born outside the earth were brought back. Technically they were aliens and they entered earth!

Crickets – Nature’s Weather Reporters

By Anupum Pant

Background

An annoying Cricket’s treet-treet-treet noise is really unbearable sometimes, especially when a house cricket ends up under your bed and treets all night long. To others, it’s pleasing, they associate it with the night time, and it makes them go to sleep.

Whatever it is for you, there’s one interesting thing universal about that noise they make. If you can count the number of chirps, you can almost accurately estimate the atmospheric temperature using a simple formula! Good ‘ol farmers used to do this.

I know all of us have smartphones these days, so counting cricket chirps to estimate temperature probably makes no sense to you. Still, I’ve said it back then and I say it again, it’s never bad to know anything.

Here’s how you do it

For doing it, you somehow should be able to measure 14 seconds. In those 14 seconds, count the number of times a single cricket chirps. Suppose there are 35 chirps heard, you save that number and add it to 40 (always 40). And this gives you the present temperature in Fahrenheit.

35 chirps + 40 = 75 degrees Fahrenheit

Now, since only a handful of countries use Fahrenheit to measure temperature, you might want to convert it into Celsius scale. I personally am comfortable with only the Celsius scale. But you don’t have to go through the trouble of converting because, to measure the temperature in Celsius scale using the cricket’s treet, this is what you have to do.

Simply count the number of chirps it makes in 25 seconds. Now divide the number by 3 and add 4 to it. There you have your ambient temperature in Celsius scale. Suppose the cricket chirps 50 times…

(50 chirps/3) + 4 = 20.67 degrees Celsius 

Why it works

To know that it is first important to understand how a cricket makes that sound. Remember only male crickets of a few species make this sound. They do this by a process called stridulation – rubbing 2 body parts to make a sound. Rubbing the underside of one wing with the upper side of the other wing does this trick – as they have rough and hard structures over there.

To move these wings it requires a particular chemical reaction to happen in their muscles. The speed of this chemical reaction is dependent on how hot or cold it is. The hotter it is, the faster the reaction happens and the faster it is able to move its muscles to produce more sounds in those 14/25 seconds…

via [Scientific American] and  [Howstuffworks] and [Farmer’s Almanac]

A Chicken’s Remarkable Image Stabilization Ability

By Anupum Pant

Background

I saw this Smarter everyday video, made by Destin, a very long time back and I remember very well that I had stored it away in my notes somewhere to share it with you guys in the future, but it was nowhere to be found. As time passed, I totally forgot about it. Just yesterday, while writing about how chicken heads saved Switzerland from rabid foxes, there was a sudden flash in my mind and I recalled having seen Destin’s video (I don’t know how that happened. Brains are amazing). I’ve attached it below for you to see.

In the video, Destin demonstrates how chickens have an amazing ability which enables them to keep their heads perfectly stable. It is just one of the many ways birds are better than humans. Irrespective of how their body moves, their head remains perfectly still in a way that their eyes are able to see a very stabilized image.

It is interesting to note that it isn’t just chickens who have this ability. Owls and a couple of other birds have this built-in too. In fact, cats can do it to some extent too, but chickens and owls are definitely better at it.

NASA, before it had sent humans to space, conducted a similar experiment with owls with an expectation that they would learn something that’d help them reduce trauma to humans in space. This is how an owl was moved around by them in every axis possible. It passed every test they threw at it. Look at it go…

The Vestibular Ocular reflex system

Most vertebrates have this device inherently built into their inner ears which has three tubes (probably to detect movement in all three dimensions). The biological device is called the Vestibular system. This is what it looks like. You can clearly see the three semi circular tubes coming out.

These three tubes are filled with a fluid which moves around when the head moves. As the fluid moves, it pushes something called a cupula and converts mechanical movement into an electrical signal. The signal is sent to the brain to process.

As a result, the brain sends back information to the eyes and moves them in the opposite direction. That is how your eyes are involuntarily able to stay focussed at a single point even when you move your hear. This is called the Vestibular ocular reflex system.

But the chicken’s eyes don’t move, so it isn’t probably correct to call it an ocular reflex. Instead their whole head moves in the opposite direction to their body movement. Thanks to the vestibular system. I’m not totally sure, but this could have something to do with righting reflex – the same thing that makes cats turn the right side up when they fall. Please help me with this in the comments section if you know more…

Chicken steady head cam

Using the same amazing biological image stabilization technology that was at his disposal, a youtuber decided to tie a camera to the chicken’s head to make a steady headcam. I think it’s an amazing idea for R&D.

This Green Slime Like Thing is a 3000 Year Old Plant

By Anupum Pant

It looks like moss, but it isn’t. Nor is it slimy.

This gooey or slimy looking thing is actually a plant which grows in Bolivia, Chile, Argentina and Peru, up in the Andes at altitudes between ten to fifteen thousand feet. Believe it or not, some of these plants are more than 3000 years old. Yes, they are one of the oldest living organisms on the planet earth – older than the golden age of Greece.

Even though the plant looks slimy goo-like from a distance, when you go closer, it is actually solid and dry to the touch. The surface of the plant consists of densely packed tens of thousands of tiny buds and flowers which make the surface feel like a pillow. That is the reason it is also  known as the Andes Pillow. In fact the surface is so stiff that a person can lie on it and the plant won’t get crushed.

It is sort of a cousin to parsley and carrots. And it is interesting to note that the plant smells like mint. Locals often boil it in water and use it to cure muscle pain.

Llareta grows extremely slowly. It grows about 1.5 cm every year. The ones which are about 2.5 to 3 meters in size can be said to have grown for hundreds of years to reach that size.

Since Llareta is dense and dry, it burns like wood, and has been known to be used by the climbers/hikers to make fire. Some say that it was also used in steam engines instead of coal. This careless burning of the extremely slow-growing living museum has endangered their long-term survival.

via [RadioLab]

Eyes of the Mantis Shrimp – Colours and Hexnocular Vision

By Anupum Pant

Of course there’s a lot of other things to talk about the Mantis Shrimp. But today, I’m going to only talk about its eyes.

Colours

The eyes of a Mantis Shrimp are one of the most advanced eyes on the planet. To realize how extraordinary their colour vision is, you need to have some perspective on what we are talking about.

Colour is just a trick of our mind. What we see is really out there, there’s no way to know for sure if it is the reality. Or, there’s no way for us to explain what we really see.

For instance, imagine how we see the world, say particularly, the colour red and all its derived colours. Now, what you see is very different from how a colour blind person or a dog sees it. Dogs and about 10% of men who are colour blind can’t see colours like we do. That is because, instead of 3 cones (red, blue and green sensitive ones), they just have two. If you and a dog would point their eyes towards the same rainbow, both of you would see a very different image (if you are not colour blind).

A dog probably would see a rainbow which would start with a blue colour and then there’d be green in it for a dog. Nothing else. That is because it has no red sensitive cones. A single difference in the number of types cones can make such a huge difference in the colour vision. Addition of the single red sensitive cone enables us to see a whole set of new colours.

Some women (estimated to be about 2-3%of the world’s population!) have a super-human ability that makes them able to see a whole set of new colours. Like we see a million different colours, these women can probably see 100 Million different colours. It’s hard to imagine what they really see. Probably that is why they say men are so bad at colours.

Similarly, consider a butterfly. They have 5-6 different kinds of cone receptors. So, when they look at a rainbow, they probably see a range of colours between the blues and the greens and the greens and the yellows. Of course, it can also see an ultraviolet beyond the violet. Incredible enough.

mantis colour range

The Mantis Shrimp, an animal of the size of your finger, has one of the most amazing colour visions. It has 16 different types of cones. You can’t even start to imagine how the world looks to them. And suppose they try and see a rainbow, they’d see a really rich set of colours. No other animals we know have even a visual system that is half as advanced.  There’s no reason they must have this ability.16 is just too many cones!

Needless to say, these technological marvels can see ultra-violet light, infra-red light, and some can even see polarised light.

Hexnocular vision

tumblr_ljijxhMzSC1qfcmjd

Now, we see with our two eyes and call it a binocular vision. We have 2 eyes and 1 focal point each. So, to see in 3-D, we need both out eyes.

Mantis Shrimp, however, has 2 eyes with 3 focal points each. Each of its eye is divided into 3 sections and can see 3 different images, using the 3 different sections. It doesn’t need 2 eyes to see in 3-D. One is enough. Besides that, it is able to judge depth much better than we are able to do it. Think of an image stitched out of 6 different eyes.

An Incredibly Simple Way to Kill A Tree

By Anupum Pant

Background

Of course, killing a tree is something I’d never want to do. I see them as old and wise people who have grown and matured for years. Plus they give us so much in return. And yet sometimes, they say, there are good reasons to kill a tree. I’ll probably never understand.

Anyway, I thought it’s good to know, just for the sake of knowing that there is an incredibly simple technique that is often used to kill trees (for legit reasons) and is widely known among horticulturists. I learnt about it just today, and I felt it was worth sharing.

It’s called Girdling (also known as  ring barking or ring-barking). Or, a technique which involves removal / peeling of a ring of bark from a tree, and the phloem layer (Like shown in the picture above). Yes, that’s it, this kills a tree. And it’s slow death. A tree which gets girdled dies gradually in about a year or more.

This is why it works…

The central part of the tree trunk (wooden part) is involved in taking the nutrients and water up to the leaves. The leaves then get exposed in the sun and mix in carbon dioxide to make sugar and other reduced carbon compounds. Most of us know that. But this is what not many know…

The outer part of the trunk – the bark and the phloem layer – also has a solid function that sustains growth and function. It’s responsible to carry the sugar (and other stuff) made by the leaves, back to the root. That is basically food to sustain growth and function of the roots. If that doesn’t reach the roots, the roots don’t receive what is required for their growth and function. Girdling does exactly that – cuts off the down-flow of food. As a result, the root dies and with it dies the whole tree. All of this happens very slowly.

To be noted

Jumping the Girdle: Some times, trees are able to repair this damage. It’s called a jumped girdle. To prevent that from happening, often smear herbicide over the girdled area.

Better Fruits: This technique is also used by some farmers to force the tree to bear better fruits – as no sugar goes down into the roots – the fruits are usually bigger and better if they come from a girdled tree. Of course these better fruits come with a price.

Girdling is particularly a good way to end trees like Aspens because as we know from Pando, many other Aspens can sprout up from the roots and cause a bigger mess if just the top part of this tree is cut off.

Girdling is a better way to kill a tree because it gives the environment time to adjust, also it is cheaper and prevents damage to the other delicate plants around the tree.

[Source]

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Australian Bird Makes Camera Shutter Sounds

By Anupum Pant

Until now I hadn’t even heard about, probably the most well-known bird of Australia, the Lyrebird. These birds are there on the 10 cents coins in Australia. Their feathers are beautiful, but what these birds can do is truly astonishing – The R2D2s of the real world.

The Lyrebird has been seen mimicking the sounds of at least twenty other birds. That’s not all. Some of these captive Lyrebirds have been seen mimicking sounds of human technology like a camera shutter, car alarm and a chainsaw too – as seen in the video below.

In 1969, as observed by an ornithologist in New England National Park, these birds were able to reproduce sounds of a flute, singing two famous songs of the 30s “The Keel Row” and “Mosquito’s Dance.”  They had learnt it from a farmer who used to play these tunes on a flute.

A word of caution

Although the video would lead you to believe that wild birds have started mimicking sounds of human technology, it isn’t totally true. The birds that has been shown in the video, in reality, are captive birds from Healesville Wildlife Sanctuary and from the Adelaide Zoo. While Attenborough makes it seem like the bird is mimicking “sounds of the forest”. these clips are not typically what these wild birds do in the wild.

Maybe it happens in the wild too, but it’s highly unlikely because the human technology sounds are usually lost amidst the forest sounds. Moreover, never in the past has there been a recording of this bird mimicking human technology sounds in the wild. Maybe they do, but science requires evidence.

Brass Doorknobs of Public Restrooms

By Anupum Pant

I remember my grandma telling me to keep some water overnight in a copper pot, and in the morning, she used to drink it. I never understood why she did that. Backed by solid science, today I’m able to appreciate her age-old wisdom.

Today, to get rid of the problem causing bacteria, trusting brass doorknobs is better than trusting those triclosan lad anti-bacterial soaps. Yes, brass can kill bacteria very effectively.

Doorknobs are probably the most touched objects, especially the ones that are on the doors of a toilet at the mall. A doorknob probably even beats smartphones because a doorknob is accessible to anyone and everyone, whereas a smartphone is usually touched by a single individual.

Although, I’m not totally sure that a doorknob is really one of the most touched objects, one thing is for sure – Door knobs are the places where an incredible amount of sickness causing germs get collected. Thanks to the thousands of unclean hands coming straight from the toilet and touching the knob for the day.

And yet, you don’t often get sick after touching public restroom knobs. That is because doorknobs are normally made of brass. Brass and a couple of other metals have an ability to clean themselves – in a given amount of time these metals are able to sterilize themselves! This is called the Oligodynamic effect. Sounds like a cool name to remember because it’s easy to remember and nothing else would annoy your friends more than you bringing it up amidst conversations…

It has been tested and found that brass is able to sterilize itself in the span of eight hours. While some have tried to explain how it works, no one has been able to explain the effect in a satisfactory manner.

Other metals like silver, copper and copper alloys are able to kill bacteria better. Silver, purportedly is a very robust disinfectant. But, not many would be able to afford doorknobs made out of silver or pure copper. Instead, a far cheaper alloy consisting of copper and zinc (brass) is used to make bacteria zapping doorknobs.

Stainless steel and aluminium metals aren’t able to do this. Be careful when you have to twist doorknobs made of Steel or Aluminium. These are metals that could get you sick.

[Wikipedia]