What makes a popping sound when we crack our knuckles?

After completing a tough task many people show their exhaustion by bending their fingers and producing that popping sound. Some people do it out of boredom and some do it for fun.  But what is it that produces this sound? Many theories have been given like rapid stretching of ligaments and intra-articular adhesion being broken, but the theory of cavitation is most plausible.

Joint anatomy- Our joints consists of two bones coming together without touching. If the bones touched then they would grind against each other with time. Our bones are covered by articular cartilage and the space between joints are filled with synovial fluid. This fluid acts as a lubricant and is produced by synovial membranes. The synovial fluid consists of many dissolved gases, mostly oxygen and carbon dioxide. These gases play an important role in knuckle cracking.

Illustration from Anatomy & Physiology, Connexions Web site. http://cnx.org/content/col11496/1.6/, Jun 19, 2013.

Cavitation- To produce that popping sound, we stretch the joints. This stretching moves the bones away from each other, increasing space between them but the amount of synovial fluid remains the same. Now, by  increasing the volume, the pressure is reduced and this reduces the solubility of gases. This is the same thing which happens when you open a soda bottle and dissolved carbon dioxide fizzes out because of fall in pressure. But inside a joint, dissolved gases can not escape the joint and hence form a bubble. This formation of bubble produces that popping sound which you hear while cracking knuckles. Some scientists believe that there might be actually two sounds, one when a bubble is formed and another when it bursts. It takes about twenty to thirty minutes for the gases to dissolve back in the fluid. This is the reason why you can not pop the same joint again for some time.

 Is cracking knuckles harmful?- Some people believe that cracking knuckles repeatedly leads to arthritis but there is not a lot of scientific data available on the topic. One study found no such relation between knuckle cracking and arthritis. According to another study, repeated knuckle cracking may affect soft tissues surrounding the joint. In 2009, a doctor named Donald Unger received Ig Noble prize for conducting an experiment on this subject.  The Ig Noble prize honours research that makes people laugh and then think. He popped the knuckles of his left hand, but not the right hand, for sixty years. His left hand did not develop any issue.

So, next time you pop your knuckles, remember that, it is possible because of dissolved gases in your synovial fluid which is playing this sound at your command. We know now that whether you are popping a bubble wrap for time pass or popping your knuckles, both have one thing in common, the bubbles. 

References-
http://health.howstuffworks.com/human-body/systems/musculoskeletal/question437.htm
http://www.scientificamerican.com/article/what-makes-the-sound-when/
http://www.livescience.com/9729-knuckle-cracking-ig-nobel-prize.html
https://en.wikipedia.org/wiki/Cracking_joints

Do plants feel pain?

Have you ever been pricked by a thorny plant while strolling in a garden? You would have certainly disliked it as it is a painful experience. But have you ever wondered if plants could also be feeling pain? Humans, in general, are against causing any pain to other humans. We also have strong laws against it. We also talk about not causing pain to other animals and it is good that things like animal rights do exist. But we never talk about the pain of trees. The reason being that we can relate to the pain of other humans and animals but not to the pain of plants. We can feel pain, so we empathise with those who can also feel pain the way we feel it, be it humans or other animals. We don't think this way about plants, possibly because may be their body structure is entirely different from ours. We forget that they also have a DNA (humans share fifty percent of their DNA with bananas). We still refuse to empathise with them and ignore that their pain might be having a different manifestation. But why do we reject this idea of plants having feelings and overlook this possibility?

Absence of nervous system- It is argued that plants are not intelligent enough to sense pain as they do not have a nervous system. This point is valid if we assume that a neural network is the only sign of intelligence and feelings in nature. But there are many areas in which plants show amazing intelligence. 

Intelligence in plants- The smartness of plants is reflected by many things. One of them is their ability to communicate with each other. Most of us enjoy the smell of freshly cut grass in summers. That smell is actually a chemical distress call by grass. Different scents are given out by plants for different types of threats. For example, when there is a threat from caterpillars, a scent is given out which makes neighbouring plants to become bitter and this bitter taste is disliked by caterpillars. Also, when a plant senses that it is under attack, it tries to attract other helpful creatures which might kill attackers. Plants can also communicate through roots (like the movie Avatar) and pass useful information about diseases to their neighbouring plants. And, plants like dodder can locate and move towards their host. Intelligence of plants is also proven by the fact that they can sense gravity and light and then grow accordingly (check out this link).

Finding feelings - An Indian scientist J C Bose (one of the fathers of  radio science), conducted experiments on plant perception in 1900. He found plants responded to a shock by spasms just like animals.  He demonstrated the electrical nature of conduction of stimuli like wounds and cuts in plants which were earlier thought to be of chemical nature. He also claimed that plants have feelings by observing the variation in cell membrane potential under various circumstances.

    

 According to researchers at University of Bonn, plants cry and signal it by releasing gases. By using a highly sensitive microphone, scientists have observed sound waves produced by plants releasing gases when injured. Cucumbers have been sensed screaming when sick and flowers crying when their leaves are cut. But at the same time, many experiments have shown no such emotions in plants.

So, we can not exactly say whether plants have feelings or not as there are no concrete results and scientific consensus is missing. But then, we also do not exactly know so many things about working of plants. We can neither accept nor reject the idea of plants having emotions. Plants are obviously not like a piece of rock. They are surely much smarter and can sense their environment. We know now that plants might be feeling pain even without a brain.

References-
http://science.howstuffworks.com/life/botany/plants-feel-pain.htm
https://en.wikipedia.org/wiki/Plant_perception_%28paranormal%29
https://en.wikipedia.org/wiki/Jagadish_Chandra_Bose
http://www.mirror.co.uk/news/weird-news/humans-share-50-dna-bananas-2482139

Death of Bees and future of crops- An extinction we cannot afford

To Bee, or not to Bee, that is the question. According to a report published by a UN body on biodiversity, the population of pollinators like bees, birds, beetles, butterflies and other species is on a steady decline and this poses a serious threat to the food crop production of the world. In recent years, bee keepers around the world have witnessed 30% to 90% loss of colonies. About one third of food crops are pollinated by bees and other small animals. So, losing these pollinators also means losing many of the food items that we consume regularly which include apples, mangoes, rice, wheat etc. Although, I do not want to put a money tag on this loss and death of bees is itself a depressing issue, but since some people understand things only in terms of money, it is estimated that the loss to crops could be from $235 to $577 billion annually. Since, most wild flowering plants(about 90%) depend upon animal pollination, they are under greater risk. I will focus more on bees here but it does not mean that other pollinators are not important.

Colony collapse disorder- It occurs when majority of worker bees in a colony disappear leaving behind queen, food, few nurse bees and other baby bees. It has affected many parts of the world in the last decade. Many European countries have reported greater than 30% decline in bee hives. In 2012-13, colony collapse disorder was held responsible for the loss of half of the honey bee hives in US. But what is the reason behind this decline in population of bees? The answer is that we are not entirely sure but let us explore many possible causes.

Parasites- Acarapis Woodi is a microscopic mite which infects the breathing tubes of bees and weakens them by feeding on them from inside. Varroa Destructor is also a type of mite and is even more dangerous. These mites lay eggs on larvae of bees and they keep feeding on the larvae. The bee larvae is not killed but weakened . When it comes out of the cell, the mites are spread to neighboring cells, thus spreading infection. This cycle is completed in ten days and they grow rapidly, ultimately causing collapse of colony. These mites also spread many viruses that harm bees. But these parasites can not alone explain this steady decline.

Pesticides- The most widely used insecticides in the world today are neonicotinoids. These are neuro-active insecticides which means that they kill insects by harming their nervous systems or their ability to sense world. It can be called as the most inhuman way of killing anyone. In high doses, it leads to convulsions, paralysis and death. In small doses, it causes bees to lose their navigation ability, they forget their way to hives, get separated from the colony and eventually meet a lonely death. Contrary to my earlier position, I would love to put a money tag here. Global sales of nicotinoids was worth $1.6 billion in 2008. With so much money involved, the horrible effects of these insecticides are being constantly ignored.

Other possible causes- In addition to the above possible reasons, things like loss of habitat, climate change, pollution, other human activities etc. are also causing damage to bees and other pollinators. If we want to keep enjoying our plates full of various delicacies and if we want to let our future generations also experience that buzz sound in the gardens, we must protect these little pollinators. Currently, their colonies look much wiser than human colonies.

We know now that when it comes to saving bees, to Bee is always better than not to Bee.

References-
http://edition.cnn.com/2016/02/26/world/un-bees-and-butterflies-report/index.html
http://www.theguardian.com/environment/2016/feb/26/decline-of-bees-poses-potential-risks-to-major-crops-says-un
http://www.onegreenplanet.org/animalsandnature/why-bees-are-important-to-our-planet/
https://en.wikipedia.org/wiki/Colony_collapse_disorder
 https://www.youtube.com/watch?v=GqA42M4RtxE
https://en.wikipedia.org/wiki/Neonicotinoid

How do plants know in which direction to grow? Plants are very smart.

You reap what you sow but seeds that you sow somehow tend to know that they have to send roots downwards and stems upwards. It does not matter in what position you sow seeds, they always grow the right way. How does a seed know which direction is right? From where does a small seed get all this intelligence?  This question intrigued scientists for a long time.

The mystery- Suppose you have a seedling in a pot and you turn it upside down, then the stem will take a U-turn and start growing in upward direction against the gravity. So, the stems always grow in a direction opposite to gravity and roots always grow in the direction of gravity. In short, plants can sense gravity.  In another experiment, a bunch of seedlings were attached to a disc and the disc was rotated at high speed. This rotating disc made seedlings feel a continuous centrifugal force radially outwards from the disc. Such a force can be called as simulated gravity. After continuous rotation, it was observed that plants responded to simulated gravity and their stems grew towards the center of the disc and roots outwards. Also, when seedlings were grown in space where there is almost no gravity, the roots grew in all the directions without any pattern. All these experiments proved that plants can sense gravitational pull. This phenomenon is known as gravitropism.

 Gravitropism- Growth movement by a plant or fungus in response to gravity is known as gravitoprism.Most evidences support that growth in response to gravity is due to regulated movement of plant hormone called auxin. Now the next question is what causes this regulation of auxin in accordance with gravity? This is where statoliths come into picture.

Statoliths- These are parts of a special subset of cells present in the root tips. These statoliths are dense and can sediment according to the direction of gravity. This sedimentation transmits a signal which leads to reorientation of auxin efflux carriers and subsequent redistribution of auxin in the root. And this change in concentration of auxin causes roots to grow in the direction of gravity. Similarly, statoliths are also found in stems and guide their growth in direction opposite to gravity. But gravity is not the only thing which affects the direction of plant growth.

Phototropism- It is the growth of an organism according to a light stimulus. It can cause a plant to grow towards light (positive phototropism) or it may cause growth away from light (negative phototropism). Here also auxin plays an important rule by changing the growth of cells according to light stimulus.

So, a tiny seed not only contains a life in an embryonic form but we know now that it also knows how to reach out for the sky but keeping feet on the ground.

References-
http://www.npr.org/sections/krulwich/2012/06/21/155508849/how-do-plants-know-which-way-is-up-and-which-way-is-down
http://blogs.scientificamerican.com/artful-amoeba/roots-down-shoots-up-but-how-does-a-plant-know-which-is-which/
https://en.wikipedia.org/wiki/Gravitropism
https://en.wikipedia.org/wiki/Phototropism

V know now gets Liebsters

It is a great pleasure to announce that I have received Liebster Award. It is an award given to new bloggers by other bloggers. I was nominated by Kayla from lacesuperheroeslife 
It is so nice of her and I am really thankful to her.

The rules of this award are very simple-
1. First, you have to show recognition for the person who nominated you (that person surely deserves it)
2. On nomination, the person will give you a list of 11 questions and you have to answer these questions in your post.
3.You need to tell your readers about yourself by giving 11 random facts about yourself.
4. You have to find 11 new blogs which deserve the nomination for Liebster award.
5. And lastly, you have to give your nominees a list of 11 questions to answer on their blog.


So, my answers to the questions asked are -
1.What is the most exciting thing you have ever done?
Ans-Riding a tractor on sand dunes.
2. What is your favorite restaurant?
Ans-I love eating at traditional Indian Dhabas (roadside restaurants). I particularly like the ones at Murthal near Delhi.
3.   If you could re-do your high school years over again, would you?
Ans- Yes, I would and I will study only what I like and leave rest.
4.Who inspired you to start your blog?
Ans-Michael Stevens from YouTube channel Vsauce.
5. What is your all time favorite TV show?
Ans-The Big Bang Theory
6. What has been your most rewarding accomplishment?
Ans- Being able to understand at least few things in this vast ocean of science.
7. If you could have a conversation with any person, living or dead, who would it be?
Ans- Albert Einstein
8. What is your lifetime goal?
Ans- To contribute something good in the field of science
9. If you had one million dollars, but could only buy one type of thing with it…what would you buy?
Ans-I would buy lots of tablets with educational stuff stored in them and then distribute them among not so fortunate kids.
10. Who is your favorite author or poet?
Ans-Dan Brown
11. What is your biggest fear?
Ans -Nothing. By nothing I mean having nothing to do. Being bored to death is what I fear.

11 random facts about me

1. I am an engineer
2. I am a very curious person
3. I am also an amateur cartoonist
4. I like programming.
5. I have spent most of the time of my life in Delhi.
6. I like to try different kinds of food items.
7. I love watching YouTube Science related channels.
8. I like playing table tennis and cricket.
9. I prefer tea over coffee.
10. Cooking is a stress buster for me.
11. I love nature.

My nominations are-

1.  Naztrends
2.  Delhifoodieblogger
3.  Tipsfornewbloggers
4.  Georgeforaday
5.  Alfalifestyleblog
6.  Unlockedsuccess
7.  Templatesgeek
8. Falution
9.  Thecolourclub
10.  Footloosedev
11.  Myanomaly

My questions areas as follows-
1. Is your hobby also your career? If not, would you like to make it that way?
2. Given a chance, what would you like to change about this world?
3. Do you have any superstition? If yes, what is it?
4. What inspired you to write this blog?
5. If you could time travel but only once without being able to return, which time would you like to go to?
6. Which super power would you like to have?
7. Which is your favorite means of transportation?
8. Which is your favorite movie?
9.  If you had an option to take over a company and become its head, which company would it be?
10. Which is your dream destination?
11. In your opinion, what is your biggest achievement?

Thanks all.

Are you really you?

Who am I? Have a you ever read a spiritual article and come across this question. But don't worry, I am not going to talk about your soul and spirituality. But still, I wish to ask you this question. What would be your answer when asked - who are you? Some of us will say their names and some will talk about their other credentials. But what makes you different from other animals? Some will say that "I am a human". But are we really humans? Let's see why we can't technically call ourselves humans.

Microbial world in you- A human body consists of many different types of bacteria and their population outnumbers the human cells. According to earlier estimates, microbes outnumber human cells in the ratio of 10 to1. However, this figure has been revised recently in favor of human cells but still the ratio stands at 1.3 to1. A standard man who weighs 70 kilograms, 20 to 30 years old and 1.7 m tall, consists of on an average about 30 trillion human cells and  40 trillion bacteria. The number of different species in human gut lies somewhere between 300 and 1000, with most estimates at about 500. Most of this bacteria is not harmful to humans at all, but rather assists in maintaining health. These microbes help in the digestion of unutilized  energy substrates.

Human cells heavy hitters- The cells which are most numerous are red blood cells which are around 24.9 trillion. But the cells which contribute most to our mass are muscle cells. Since, women have lesser blood volume, so their bacteria to human cell ratio may be 30 percent higher than that of men.

 Toilet makes you more you- Most of the bacteria live in our colon which is around 39 trillion. Through every bowel movement, you get rid of a few trillion bacteria and the ratio is flipped in favor of human cells. So, if some wise person advises you to be yourself, then you must clarify whether he wants you to go to toilet.

We know now that if you really wanna be you, go to the loo.

References-
https://en.wikipedia.org/wiki/Human_microbiota
http://www.nature.com/news/scientists-bust-myth-that-our-bodies-have-more-bacteria-than-human-cells-1.19136
https://www.sciencenews.org/article/body%E2%80%99s-bacteria-don%E2%80%99t-outnumber-human-cells-so-much-after-all
https://en.wikipedia.org/wiki/Gut_flora

How empty are we? A nerdy challenge.

Anna invited his three friends Raga, Arke and Namo to his home for a party. The party was going on very well and they discussed many issues. Slowly, the discussion heated up and Raga said that he was the most intelligent among those invited. But Arke and Namo also made similar claims. This annoyed Anna and to resolve the issue, Anna gave them a challenge and whosoever won was to be given a dollar each by other two. They sat around a table and Anna started pouring water into a glass and filled it up to the midpoint of its height. Then they had the following conversation-

Anna- On by one, you have to tell me whether this glass is half empty or half full. One who gives the right answer will win. Raga, you tell first.
Raga- Obviously, it is half empty.
Anna- And you Arke?
Arke- No, I think it is half full.
Anna- And what do you think Namo?
Namo- It is neither half empty nor half full. It is half filled with water and half filled with air. So, it is completely filled.
Anna looked at all them with disappointment.
Anna- Unfortunately, you all are wrong. Now stop fighting and enjoy the party.

But, how were they all wrong?  This is because Anna was smart and he knew that everything around us is pretty empty. Even a glass full of water is actually empty. To believe it we need to look things at the atomic level.

Amazing atom- You and all the things around you are made up of atoms. An atom is made up of a nucleus surrounded by a cloud of electrons. Nucleus consists of protons and neutrons. Protons and neutrons are made up of quarks. Electrons orbit around the nucleus at the speed of 2,200 Km/sec. At this speed you can travel around the earth in about 18 seconds. But the fact which Anna used is that an atom is 99.999999999999% empty space. If an atom would have been of the size of a football stadium then the nucleus would have been of the size of a pea at the center of the stadium.

Since, an atom is mostly empty space and everything is made up of atoms, we can say that everything is almost empty. But that empty space is not really empty and consists of quantum fluctuations. So, Anna could have given benefit of doubt to Namo but Anna was not in the mood of letting any of them win. 

Now, whenever we feel sad and have that feeling of emptiness, we know now that we were always like this, quite empty.

Resources-

https://en.wikipedia.org/wiki/Atom

https://www.youtube.com/watch?v=_lNF3_30lUE

Mobile phone radiation and its effects on living beings

Mobile phones have become an integral part of our lives. So much so that, a cellphone can be called as an extended part of our bodies. We start feeling uneasy when separated from our phones. There are more than 4 billion mobile phone users in the world. Mobile phones have made our lives much easier by enabling us to remain connected to the rest of the world. But as with most scientific inventions, there are some side-effects. We are continuously surrounded by radiation from mobile phones and mobile towers. Whether this radiation is harmful to living beings or not is still debatable. There have been many studies carried out on the subject. Before discussing them, we first need to understand what are ionising and non-ionising radiations.

Ionising radiation- If a radiation carries enough energy to knock out electrons from atoms or molecules, then such radiation is an ionising radiation. Gamma rays and X-rays are examples of ionising radiations. This type of radiation is harmful to living beings. Exposure to such radiation can lead to burns, cancers and genetic mutations. So, it is better to stay away from them, unless you want to mutate to get supernatural powers but chances of death after such exposure are much much higher than turning into spiderman.

Non-ionising radiation- If an electromagnetic radiation does not carry enough energy to knock out electrons from atoms or molecules, then such radiation is non-ionising radiation. Sunlight, infrared waves and mobile tower radiation are its examples. They do not produce any lethal effects in living tissues like ionising radiation.

But is exposure to mobile phone radiation completely safe?   In 2011, International Agency for Research on Cancer classified mobile phone radiation as possibly carcinogenic. But WHO added that "to date, no adverse health effects have been established as being caused by mobile phone use". The mobile phone radiation does produce a heating effect and leads to rise in temperature of the surface of the head by a fraction of a degree. But this rise is smaller than the increase in temperature of head under direct sunlight. And to find a link between cancer and mobile phone usage, a Danish group followed 420,000 citizens for 20 years and they showed no increased risk of cancer. But in 2007, a Swedish scientist found that cell phone users had increased risk of tumors and these tumors are more likely to occur on the side of the head that the mobile handset is used. So, we are still not sure whether that next call to your friend is taking you closer to tumor or not. But what about animals? They are also exposed to mobile radiation from towers all the time. Have they been affected in any way?

Effects on other living beings-In 2010, a group of experts in India reviewed 919 studies performed worldwide regarding the effects of cellphone towers on birds, insects, animals, wildlife and humans. Out of the 919 studies, 593 showed that mobile towers radiation had negative impact on animal life. They also held it responsible as a possible cause of decline in population of some species. In another study by Centre for Environment and Vocational Studies, Punjab, 50 eggs of house sparrows were exposed to EMR for 5-10 minutes and all the 50 embryos were found to be damaged. There has been a massive decline in population of house sparrows in most Indian cities in recent years. In 2014, an environmental science experts team attributed this disappearance of house sparrows to mobile radiation. According to them, long term exposure to mobile radiation has damaging effects on the nervous and immune system of small animals. Also, many species use magnetic navigation and mobile radiation can interfere with their sensors and misguide them while navigating and preying.

So, that shiny smart phone in your hands is radiating waves which may or may not be harmful to us but it looks as if they do have a negative impact on our smaller partners on this planet. We know now that our desire of staying connected might be getting fulfilled by the lives of birds and insects. Let's hope that future studies prove this wrong.  

References-
http://timesofindia.indiatimes.com/home/environment/pollution/Mobile-tower-radiation/articleshow/32348258.cms
http://naturalsociety.com/cellphone-tower-emr-damaging-birds-insects-humans/
http://timesofindia.indiatimes.com/city/nagpur/Radiation-from-mobile-towers-affect-birds-MoEF-study/articleshow/10487141.cms
http://www.moef.nic.in/downloads/public-information/final_mobile_towers_report.pdf
https://en.wikipedia.org/wiki/Non-ionizing_radiation
https://en.wikipedia.org/wiki/Ionizing_radiation
https://en.wikipedia.org/wiki/Mobile_phone_radiation_and_health