That Sweet Scent of Rain

by Anupum Pant

When rain starts falling after a long dry spell, most of us notice a sweet-musky scent around us. Sometimes, it is as if you can smell the rain coming. Have you ever wondered what causes this peculiar smell?

Well, scientists have also wondered the same for a long time and now they have some concrete answers for us. According to them, this evocative scent is a mixture of several individual smells. In essence, there are three factors which combine to form the “petrichor” – The smell of rain.

  1. Bacteria – The best (my favorite) of all the three is caused because of a specific type of bacteria in mud called Actinomycetes. The force, with which the rain water falls, disrupts the bacteria-produced-spores in dry mud, and the moisture present in the air carries them to our noses. Most people love this odor and associate it with rain.
    So, spores of bacteria are responsible for the kind of smell you get, when rain falls on dry mud.
  2. Plant Oils – A blend of oils produced by plants during the dry spell is another main source of this aroma. When it rains, volatile parts of these oils get released into the air. It is the kind of smell you get when you are getting wet in the woods.
  3. Ozone – Another smell associated with the rain, is a minor part of petrichor and it smells like burning wires. This is produced by a reaction caused when lightning strikes, the Nitrogen and Oxygen present in air to form Ozone molecules.

Subjective senses

Besides that, smell is a subjective sensation. That means, you can’t explain a smell to someone, and you can never know what the other person smells. So, it becomes really hard for scientists to communicate to us, which scent is which.

Some of us like the bacteria smell, while others might like the third component of petrichor.

Some like the smell of rain, others don’t. But we’ll never know accurately, if the scent you adore is the same as the one your friend hates. One way to communicate some information about these scents is by comparing them with other popular smells (like I did above). This could probably give you a vague idea, but the exact sensation will remain elusive. It is like trying to explain the color red to a person who’s been blind all his/her life.

Bats Can See

by Anupum Pant

While every teacher around the world is busy teaching their kids that bats are blind, the contrary is actually true. Bats aren’t really blind and they can see pretty darn well even in low light. In fact, their eyes work better than our eyes do in a dimly lit environment (eg. Moon light).

None of the bats’ 1100 species are completely blind. Although, there are a few which depend heavily on a technique called echolocation to navigate around objects which are near, they still have to use eyes to see objects which are far away. Additionally, most bats like to hunt in complete darkness (to avoid competition from other birds), so they use echolocation during such times [because eyes need at least some amount of light to be present]. The daylight hours spent by them to groom or sleep don’t demand much of their visual skills, but that doesn’t make them blind.

One way in which bat’s vision is poorer than our visual ability, is that they can’t see colors like we do. Everything they see is in black and white. This disability, if you may call it one, is compensated by their ability to detect light waves whose frequencies lie beyond the human visible spectrum. Flying foxes, however, which are actually bigger bats, can see colors.

So, simply put, bats can see, but they don’t have to use their eyes to hunt or move around. This makes your teacher wrong when he/she says chides you with the phrase – “Blind as a bat”

Bonus Bat Facts

  1. Bats don’t carry rabies. However, like humans, the disease affects some bats.
  2. Apart from vampire bats found in Mexico, Central America and South America, no other bats suck blood.
  3. Bats hunt insects above your head, they aren’t interested in your hair or your eyes.
  4. Bats can catch insects with their tail or wing membranes.
  5. Fruit bats are also known as flying foxes, they eat fruits.
  6. Bats collectively eat tonnes of insects and protect our crops.
  7. Some bats eat fish and frogs.
  8. Bats’ dung, is rich in nutrients. It is mined from caves, bagged, and used by farmers to fertilize their crops.

Echolocation: A bat echolocates by sending out streams of high-pitched sounds through its mouth or nose. These signals then bounce off nearby objects and send back echoes. By “reading” these echoes with its super-sensitive ears, the bat can determine the location, distance, size, texture and shape of an object in its environment. In some cases, a bat can even use echoes to tell insects that are edible apart from those that aren’t. – [Source]

 

Horror Movies are Good for You

by Anupum Pant

It is Halloween today and most of us must be busy making plans for the day. But if you’ve missed including a horror movie in your plans, after reading this post, you might want to consider putting it in the list.

Studies have shown that watching a horror movie can actually be beneficial to your health. In two separate experiments, scientists were able to record two different ways in which horror movies can be good for you. Of course, this shouldn’t encourage extremely sensitive people to force horror movies onto themselves. In spite of these proven benefits, pregnant women, old men, little kids and people with heart disorders must try to stay away.

Moreover, the benefits found, were not practically too big. So, if you are thinking of leaving your healthy diet plan and making up for it by starting to watch more horror movies, you are mistaken. But, scientifically, the discovery of such co-relations are considered as noteworthy.

The first study (increase in immunity)

Researchers suggest that while people watch horror movies, their brain secretes chemicals like dopamine, glutamate and serotonin. As a result, there is an increased brain activity, which makes the mind alert for a while. Additionally, threat signals that pass through the brain stimulate adrenal glands to produce adrenaline, which has an anesthesia like effect.

Secondly, a half-hour watch was found enough to boost the number of active white blood cells in their blood – they are responsible to keep diseases away. In the test, a first time watch of Texas Chainsaw Massacre by 32 men and women led to an increased immunity for some time. [Source Paper]

The second study (burns calories)

In another study conducted recently, scientists observed an average of 184 burnt calories among the people who watched The Shining (the 1980 thriller). Jaws took the second spot, with people burning on an average of 161 calories after watching it, and The Exorcist came third, with 158 calories. Top 5 calorie burning movies were as follows:

1. The Shining: 184 calories
2. Jaws: 161 calories
3. The Exorcist: 158 calories
4. Alien: 152 calories
5. Saw: 133 calories

Increased heart rate, muscular contractions, a surge in adrenalin, oxygen intake and greater carbon-dioxide output were the main reasons that  these extra calories got burnt. So, the next time you are watching a horror movie (working out), avoid popping popcorn. [Read more]