Science Zone

Skin As Body Temperature Regulator

<div xmlns='http://www.w3.org/1999/xhtml'>The skin as we all know is the largest organ in the body. Also with exception of the bones and cartilages, it's the toughest tissue in the body. It does live up to its status by carrying out numerous functions such as protection, excretion, storage of food, sensitivity, regulation of the body temperature, production of vitamin D through the early sunshine and so on. 
 
Today we are going to see how the skin regulates the body temperature especially in we homoiothermic animals; animals with constant body temperature. 
 
This is truly amazing as how the skin keeps the body temperature constant regardless of changes in external environment though the liquid tissue cell (blood) also plays a role at body temperature regulation. 
 
On a hot day or weather, there's usually an increase in the temperature of the environment and the skin carry out the following processes to get rid of excess heat and thus to keep the body temperature constant. 
 
VASODILATION: 
There is a dilation of the capillaries near the skin surface and a constriction of those in the deeper layer. The impact of this is a large volume of blood flow close to the surface of the skin such that there's a loss of heat via the three mood of heat transfer namely; conduction, convection and radiation. 
 
DECREASE IN METABOLIC RATE: There is a reduction in metabolic activity by the skin or body and this reduces the heat released by metabolic activity and thus heat production is reduced. 
 
LOWERING OF HAIRS: We usually notice that the hairs especially those on the hands and legs rise and fall. Yes they rise and fall. 
During hot days, the hair erector muscles relax causing the hairs to lie flat on the skin surface. This expose most of the air trapped by the hairs and also heat from the body is lost as the air evaporates. 
 
SWEATING: 
The sweat gland is usually active during hot periods and there's large sweat production. As the sweat evaporate from the skin, latent heat of evaporation is also extracted from the body hence the heat of the body is reduced. 
 
On a cold day or weather, the following processes are done by the skin to regulate the body temperature. 
 
RAISING OF THE HAIRS: 
The hair erector muscle contract to raise the hair and trap more air during a cold weather. Since air is a bad conductor of heat, the layer of air next to the skin acts as an insulator and prevent heat loss from the body and conserves the normal body temperature. 
 
VOSOCONSTRICTION: There's constriction of capillaries close to the skin surface and also a dilation of capillaries in deeper layer of the skin. This brings about small volume of blood flow near the skin surface and hence prevents loss of heat and conserves body heat or temperature. 
 
INCREASE IN METABOLIC ACTIVITY: The skin increases the metabolic activity of the body especially the respiratory activity of the liver that release large amount of energy and heat. This help to generate the heat necessary to keep the body's temperature from dropping during cold weather. 
 
SWEATING: 
THE sweat gland become inactive on a cold day and hence there is very little production of sweat that gets evaporated thereby conserving the latent heat of vaporization and rather use it to keep the body temperature constant by ensuring no drop 'in temperature rate throughout the body. 
This is the very reason</div>

Skin As Body Temperature Regulator

The skin as we all know is the largest organ in the body. Also with exception of the bones and cartilages, it's the toughest tissue in the body. It does live up to its status by carrying out numerous …

01 Aug 2015

This Friday, There Would Be a Blue Moon

<div xmlns='http://www.w3.org/1999/xhtml'>This Friday, there will be a once in a blue moon occurrence. If you step outside, you might find yourself gazing out at a brimming, full moon. 
 
Disappointingly, it won't actually be blue; the term is a misnomer. In fact, a blue moon isn't any different to any other full moon. 
In the past, a blue moon was used to mean "rare," but now the name is given to any full moon that is the second to appear in one calendar month. The lunar cycle is around 29 
and a half days, and months of the year are between 28 and 31 days long. The probability of a full lunar cycle, from full moon to full moon, 
occurring precisely during this time window is therefore not very high. 
 
The next blue moon, by this definition, is going to be on January 31, 2018 – around two and a half years from now. There will be another blue moon two months after that on March 31, 2018, 
after which it will be another two-year wait. 
 
The term "blue moon" has evolved over the last 200 years or so. Initially, a blue moon was 
based on a complicated combination of. circumstances. In one astronomical season, there are normally three full moons and if there was ever a fourth, then that would be the blue moon. 
 
However, this all changed when a hobby astronomer, James Hugh Pruett, wrote an article that was published in the magazine <a href='http://skyandtelescope.com'> 
Sky and Telescope</a> in 1946. He defined a blue moon as any second full moon in a calendar month. 
 
This definition was incorrect, but it was so much easier to understand that the world scrambled to embrace this new definition. 
 
You might be feeling a little disheartened that the moon won't be blue, but blue moons in terms of color have been seen in the past under very special circumstances. 
 
Usually, these moons are reported after a volcanic eruption or even a forest fire, which release plumes of 
particles that rise into the atmosphere. The particles happen to be the perfect size to scatter away red light, only allowing blue light through the dust cloud. Out of the ashes, a blue moon appears. 
 
<a href='http://ifls.com'>IFLS</a> 
 
<a href='https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKGRTmy_u8KSJzUAtSdW5q30iZoqGI3Rbtj_xP7kFiQ7yCeDaWQABw-k6BYNx6OkPX3MTEcuW98Df4GnI6YwdwAfv7SBZ2zYDxWjvnbj5zl_E97zo2us2WRb3dfCRAGEShxSn97qMIVe4/s2560/1438329660547.jpeg' onblur='try {parent.deselectBloggerImageGracefully();} catch(e) {}'><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKGRTmy_u8KSJzUAtSdW5q30iZoqGI3Rbtj_xP7kFiQ7yCeDaWQABw-k6BYNx6OkPX3MTEcuW98Df4GnI6YwdwAfv7SBZ2zYDxWjvnbj5zl_E97zo2us2WRb3dfCRAGEShxSn97qMIVe4/s350/1438329660547.jpeg" style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;"/></a></div>

This Friday, There Would Be a Blue Moon

This Friday, there will be a once in a blue moon occurrence. If you step outside, you might find yourself gazing out at a brimming, full moon. Disappointingly, it won't actually be blue; the term is a…

31 Jul 2015

What is Dark Energy?

Instead of pulling galaxies in our universe together, gravity seems to be driving them apart. 
How can gravity be repulsive, when our everyday experience shows it’s attractive? 
 
To explain it, we need dark energy. 
 
What goes up must come down… right? 
 
How do we think about something we can't see and don’t experience in our everyday lives, but seems to be pushing our universe apart ever faster? 
 
The nature of dark energy is one of the most important unsolved problems in all of science. 
But what, exactly, is dark energy, and why do we even believe that it exists? 
Step back a minute and consider a more familiar experience: what happens when you toss a ball 
straight up into the air? 
 
It gradually slows down as gravity tugs on it, finally stopping in mid-air 
and falling back to the ground. Of course, if you threw the ball hard enough (about 25,000 miles 
per hour) it would actually escape from the Earth entirely and shoot into space, never to return. 
 
But even in that case, gravity would continue to pull feebly on the ball, slowing its speed as it escaped the clutches of the Earth. 
 
But now imagine something completely different. 
Suppose that you tossed a ball into the air, and instead of being attracted back to the ground, the ball was repelled by the Earth and blasted faster and faster into the sky. 
 
This would be an astonishing event, but it’s exactly what astronomers have observed happening to the 
entire universe! 
Scientists have known for almost a century that the universe is expanding, with all of the galaxies 
flying apart from each other. And until recently, scientists believed that there were only two possible options for the universe in the future. It could expand forever (like the ball that you tossed upward at 25,000 miles an hour), but with the expansion slowing down as gravity 
pulled all of the galaxies toward each other. 
 
Or gravity might win out in the end and bring the expansion of the universe to a halt, finally collapsing it back down in a “big crunch,” just 
like your ball plunging back to the ground. 
 
This illustration shows abstracted ‘slices’ of space at different points in time as the universe expands. 
 
So imagine scientists’ surprise when two different teams of astronomers discovered, back in 1998, that neither of these behaviors was 
correct. 
 
These astronomers were measuring how fast the universe was expanding when it was much younger than today. 
 
But how could they do this without building a time machine? 
Luckily, a telescope is a time machine. 
 
When you look up at the stars at night, you aren’t seeing what they look like today – you’re seeing light 
that left the stars a long time ago – often many hundreds of years. 
 
By looking at distant supernovae, which are tremendously bright 
exploding stars, astronomers can look back hundreds of millions of years. They can then measure the expansion rate back then by 
comparing the distance to these far-off supernovae with the speed at which they are flying away from us. 
 
And by comparing how fast the universe was expanding hundreds of millions of years ago to its rate of expansion today, these astronomers discovered that the expansion is 
actually speeding up instead of slowing down as everyone had expected. 
 
What pushes galaxies like these in the Hubble deep field apart? 
Instead of pulling the galaxies in the universe together, gravity seems to be driving them apart. 
But how can gravity be repulsive, when our everyday experience shows that it’s attractive? 
 
Einstein’s theory of gravity in fact predicts that gravity can repel as well as attract, but only under very special circumstances. 
Repulsive gravity requires a new form of energy, dubbed “dark energy,” with very weird properties. 
Unlike ordinary matter, dark energy has negative pressure, and it’s this negative pressure that makes gravity repulsive. (For ordinary matter, gravity is always attractive). 
 
Dark energy appears to be smoothly smeared out through the entire universe, and it interacts with ordinary matter only through the action of gravity, making it nearly impossible to test in the laboratory. 
 
Scientists used to think that the expansion of the universe was described by the yellow, 
green, or blue curves. But surprise, it’s actually the red curve instead. 
 
The simplest form of dark energy goes by two different names: a cosmological constant or 
vacuum energy. Vacuum energy has another strange property. Imagine a box that expands as the universe expands. The amount of matter in 
the box stays the same as the box expands, but the volume of the box goes up, so the density of matter in the box goes down. In fact, the density of everything goes down as the universe expands. 
 
Except for vacuum energy – its density stays exactly the same. (Yes, that’s as bizarre as it sounds. It’s like stretching a string of taffy 
and discovering that it never gets any thinner). 
 
Astronomers continue to probe the skies, looking for finer details that can build on what we suspect about dark energy. 
Since dark energy can’t be isolated or probed in the laboratory, how can we hope to understand exactly what it’s made of? 
 
Different theories for dark energy predict small differences in the way 
that the expansion of the universe changes with time. 
 
Credit: www.earthsky.org 
<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQN-GY3Uyb05yrSj2CesJwRzKvQPQXMAOJOb4hkMHbO0TAlSovw5EIYqOUVoEXyfnZPQ_WdHSsfFyDMtfOBQQndO2gKV8W10WKroDNzJBa-kpprDeX3tx0LpHg-2y8ciKBxzvrNqIf1Ik/s2560/1435225523745.jpeg"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQN-GY3Uyb05yrSj2CesJwRzKvQPQXMAOJOb4hkMHbO0TAlSovw5EIYqOUVoEXyfnZPQ_WdHSsfFyDMtfOBQQndO2gKV8W10WKroDNzJBa-kpprDeX3tx0LpHg-2y8ciKBxzvrNqIf1Ik/s350/1435225523745.jpeg" style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;" /></a>

What is Dark Energy?

Instead of pulling galaxies in our universe together, gravity seems to be driving them apart. How can gravity be repulsive, when our everyday experience shows it’s attractive? To explain it, we need d…

25 Jun 2015

Weird Facts About Human Body

<div xmlns='http://www.w3.org/1999/xhtml'>> Men lose about 40 hairs in a day and women lose 70 hairs in a day. 
 
> Your blood has same amount of salts in it as an ocean has. 
 
> You are taller in the morning than you are at night. 
 
> Heart circulates blood in your body about 1000 times each day. 
 
> Eyelashes last about 150 days. 
 
> There are 500 hairs in an eyebrow. 
 
> The average human body contains 
approximately 100 billion nerve cells. 
 
> It is not possible to sneeze with open eyes. 
 
> Bones are 4 times stronger than concrete. 
 
> Average life span of a taste bud is only 10 days. 
 
> You are born without knee caps and they don't appear until age of 2 to 6 years. 
 
> Children grow faster in springtime. 
 
> Eyes stay the same size throughout life but nose and ears never stop growing. 
 
> We born with 300 bones but end up with 206 bones when we are adult. 
 
> Human skull is made up of 26 different bones. 
 
> Hair is made of same substance as fingernails. 
 
> Our entire body functions stop when we sneeze, even your heart beat. 
 
> Tongue is the strongest muscle in human body. 
 
> Typical person goes to bathroom six times a day. 
 
> Food takes 7 seconds to reach stomach from mouth. 
 
> Children have more taste buds than adults. 
 
> Sneeze blows air out of nose at the speed of 100 miles per hour. 
 
> Largest muscle in your body is one on which you are sitting on. 
 
> Smallest bone of body is in ears. 
 
<a href='https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrJgWv_hgqA1AQDLySP4WwR9i3QQ3NrgNiY0RPG_R6FmKHBv68BmF1YPZLM-i4__-TA3zcHf8MF9Bpv8pnKZDy8qhMI92q_7Ovgso4Zerbz6Pao3SLtgJIcOxolaZZS0FVcAbsvnnquqk/s2560/1434967966575.jpeg' onblur='try {parent.deselectBloggerImageGracefully();} catch(e) {}'><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrJgWv_hgqA1AQDLySP4WwR9i3QQ3NrgNiY0RPG_R6FmKHBv68BmF1YPZLM-i4__-TA3zcHf8MF9Bpv8pnKZDy8qhMI92q_7Ovgso4Zerbz6Pao3SLtgJIcOxolaZZS0FVcAbsvnnquqk/s350/1434967966575.jpeg" style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;"/></a></div>

Weird Facts About Human Body

> Men lose about 40 hairs in a day and women lose 70 hairs in a day. > Your blood has same amount of salts in it as an ocean has. > You are taller in the morning than you are at night. > Heart circul…

22 Jun 2015

How Ship's Floatation on Water Is Possible

<div xmlns='http://www.w3.org/1999/xhtml'>Why is that an iron Rod sink in water? But imagine a ship made by an iron rod does not sink? 
 
This question was asked by one of our readers and I considered it worthy of a blog post. 
 
The ability of an object to float on water depends on factors such as the nature of object, the surface area and so on. 
Let's consider the principle of floatation popularly known as Archimedes's principle, he noted that for an object to float on water, the weight of object must equal the upthrust on the object when immersed in water. 
However it's most important to know that an object only floats on a water if and only if the weight of the body equals the upthrust before it's fully immersed in a liquid. 
Have you witnessed that it's possible for a rubber cup containing water to sink in a bucket of water and a steel cup to float. The both can sink and float based on the condition stated above. 
 
Coming back to your question, you pointed out that iron sinks and so should anything made of it. That's wrong. 
Here we are talking of the surface area, ship has a large surface area and thus before it can sink, it has to displace a large amount of water and its weight on the water leads to increase in upthrust on the ship and thus the weight and the upthrust equals each other. 
The effect of surface area can be seen in this way. 
We know if a stone and a paper are fallen at a height and at the same time in a vacuum, they land the same time. Why that's is not true if done in the atmosphere is that the stone has small surface area unlike the paper. 
 
So the paper has to overcome more resistance from the air i.e displace more air to land compared to the stone.</div>

How Ship's Floatation on Water Is Possible

Why is that an iron Rod sink in water? But imagine a ship made by an iron rod does not sink? This question was asked by one of our readers and I considered it worthy of a blog post. The ability of an…

22 Apr 2015

EVER WONDER WHY BIRDS FLY IN V FORMATION

<div xmlns='http://www.w3.org/1999/xhtml'>I stood gazing in wonder when a "V" flew past over me. Not actually a letter "V", rather a flock of birds in V formation. Still watching the beautiful scenery created by those birds in the sky, I noticed the one at the rear fly past others and replaced the leader. 
 
That's awesome I said having realized they possibly continued to change position when the leader is weak as our winged friends continue their migration 
 
Why do birds migrate? 
Why do birds fly in V formation? 
Why do the even prefer V shape? 
 
Away we flock with them to find the answer... 
 
Though not all birds migrate but more than half do. They are referred as migratory birds. 
Reasons why birds migrate to a different habitat vary but shouldn't be far from availability of food or for survival purpose i.e they respond to stimuli such as changes in weather. 
 
Flying in V formation is in fact a characteristic of migratory birds. 
Reason; to save energy during their long journey. 
 
Funny enough! birds migrate several kilometers away from their habitat. Don't be surprised why they mainly feed on grains because the grains provide the energy they burn up during their flight. Flying consumes a lot energy even a pilot can tell you that. 
 
Thanks to nature that has this amazing feature bestowed to our winged friends to enable their aerial adaptation. 
 
In the northern hemisphere, many birds migrate south during the winter months when the weather becomes too cold for them to survive in their northern habitats. Once spring arrives, the birds return to their homes. Equally as varied as the reasons for migrating are the ways in which different migratory birds make their journey. Some birds migrate alone, others travel in pairs and many move in large flocks. Some birds often migrate in swarms, while larger birds, such as geese,migrate in formation. 
 
Many times this migration takes the form of the letter V. 
Why? 
The reason birds prefer to fly in a V shape has puzzled researchers for many years. There are two general theories to explain the V-shaped phenomenon. The most accepted theory is that the formation of a flock influences aerodynamics, making it easier for the birds to fly. As the birds flap their wings, the air flowing off their wing tips gives birds in the back of the V an extra lift. 
 
This reduces the amount of energy the birds need to fly. Over the course of the migration, birds take turns leading the front of the V, the most difficult position. When a bird is tired of leading, it falls to the rear of the V, where there is the least wind resistance. Rotating through various positions in the V maximizes the use of each bird’s energy, allowing flocks to fly for long periods of time without having to stop. 
 
The second theory suggests flying in a V offers each bird an unimpaired line of sight as the flick flies through the air. This makes it easier for the birds to keep track of each member of the flock. Groups of fighter pilots often arrange their planes in V formation for the same reason.</div>

EVER WONDER WHY BIRDS FLY IN V FORMATION

I stood gazing in wonder when a "V" flew past over me. Not actually a letter "V", rather a flock of birds in V formation. Still watching the beautiful scenery created by those birds in the sky, I noti…

12 Apr 2015