Veda #33 : The Rain's Smell 11:08 PM

Day 33
"Do you know what is the rain's smell?"

A few past months was the beginning of our rainy season, and up until now, maybe it always raining everyday. Lucky for me (and for you) who have a garden or live not in the center of the city (that lacks of soils and trees), you can always smell the rain and the soils. Somehow it's very vibrant and refreshing. But did you know actually what caused this and what its name?

The smell of rain in the dry grounds officially called Petrichor. More specifically, petrichor is the pleasant smell that often accompanies the first rain after a long period of dry weather. It was named by two Australian researchers, who discovered that the smell is an oily essence emitted from rocks or soils. The oil is a complicated mixture of at least fifty different compounds, rather like a perfume. (i wonder if it is gonna be a hot selling item if there are actually a perfume makers who want to make petrichor as their fragrance)

It turned out that the oils are given off by vegetation during dry weather and absorbed to the surface of rocks and soil particles, to be released into the air again by the next rains. There has been some suggestion that the smell may trigger reproductive behaviour in kangaroos and other marsupials. And for most human, they described the smell as pleasant and refreshing, and help to trigger human's memory that connected to creative side. (as for me, it definitely connect to "sleepy" side)

The word comes from Greek petros, a stone, plus ichor, from the Greek word for the fluid that flows like blood in the veins of the gods. So next time you're gonna say "i love the smell of rains", say this instead : "I love the smell of petrichor".
there, you're officially sounds way better, plus 10 for you. :))
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Veda #19 : Itchy Itchy Mosquito 10:44 PM

Day 19
Question by : ? - "Why do we feel itch and need to scratch our skin whenever mosquito bite us?"


General question tonight, maybe some of you've already know the answer to this question.
Mosquito is like a little annoying robot, they can sense us humans. With their antenna, mosquitoes can sense carbon dioxide and lactic acid up to 100 feet away. They can also detect chemicals in sweat. Since people and animals give off lots of carbon dioxide and these other chemicals, it makes it easy for mosquitoes to find us. Whenever a mosquito bite us, it'll left behind the itchy feeling to us, and suddenly we need to scratch it. why would that happen?why suddenly we feel itch?and do we really need to scratch it or not?

So to be clear, the mosquito that usually bite us is the female one. They do this because they use blood as a source of protein. Without a protein snack, a female mosquito cannot lay eggs. So when the mosquito lands, her first thing to do is to stick her long, thin sting into your skin like a needle. She injects a fluid that keeps your blood from coagulating (thickening). Then she sucks up a drop of blood, about five microliters, and stores it in her abdomen. Once she is full, she flies away to lay her eggs.

People probably wouldn't mind this so much, it's not a lot of blood from their body, but there are two problems with mosquitoes. First, diseases. When the mosquito injects this fluid, germs and parasites can enter your body. You could get malaria, yellow fever, dengue fever or West Nile encephalitis. And each of these can be fatal!
The second problem is, the fluid the mosquito injects does not belong in your body. Your immune system makes the area swell so that it can clean out the fluid, that unfortunately "disturb" our skin nerves. The whole clean up process is what makes your skin itch after the bite. So, it's not the mosquito that makes us itch, but our immune system basically.


And do we really need to scratch the itchy part?if it was caused by mosquito, go ahead, don't scratch it too hard though.
but if your skin feel any itch without any mosquitos bite, then don't. Because this itch indicating there is some abnormalities on our skin nerve, scratching it only make it worse because the allergies gonna be spreading, and make your skin wounded.
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