How mosquitos deal with getting hit by raindrops(phenomena.nationalgeographic.com) |
How mosquitos deal with getting hit by raindrops(phenomena.nationalgeographic.com) |
Check out this one: https://www.youtube.com/watch?v=8s1_f9fyjME
Still a good read with fun drawings :)
That is not a sensible comparison. When you scale something mass changes as the cube of dimension. Strength changes as the square of dimension. So small things are inherently stronger with respect to their mass.
Axial (tension, compression) and shear strength are derived from net area and so scale with by x^2. Flexural strength is derived from a factored second moment of inertia which happens to work out to x^3.
You don't have the same results from bus:human::raindrop:mosquito, but the size comparison is a useful measure. I didn't realize a raindrop was 50x the mass of a mosquito. I thought they were roughly the same size.
Further, it reinforces or introduces the idea (along with the conclusion of the study) that "So small things are inherently stronger with respect to their mass."
Lastly, this is National Geographic. Anecdotes and analogies are useful to communicate to the general public.
Well yeah, since the mosquito evidently survives...
Very believable; how does the math work out?
Interesting article, but in the span of one paragraph here we have confused velocity, acceleration, and pressure - and there are similar errors in the following one. For an article about physics, I would expect this to at least be proofread.
The Gell-Mann Amnesia effect: http://harmful.cat-v.org/journalism/
>> [Hu] and Dickerson constructed a flight arena consisting of a small acrylic cage covered with mesh to contain the mosquitoes but permit entry of water drops. The researchers used a water jet to simulate rain stream velocity while observing six mosquitoes flying into the stream. Amazingly, all the mosquitoes lived.
The researchers used simulated rain drops on six mosquitoes. There are more than six species of mosquitoes. They controlled for wind effects (which are part and parcel of rain). So they excluded horizontally travelling raindrops. My immediate reaction to the conclusion that mosquitoes can fly in rain was "Really? Not always". Here is a methodologically lacking and wholly unscientific anecdote: I have lived in Johannesburg my entire life, where mosquitoes are quite prevalent during the summer months. When it is raining heavily (it is usually quite windy as well), the local species of mosquito that feeds of humans do not present a problem as the number of airborne mosquitoes tends to zero.
Has anyone actually done any research on dragonflies being hit by raindrops, or is this just speculation?
> If you want to see this for yourself, take a look at Hu’s video
What? Nothing like that happens in it.
In the right hand panel of the video, the insect certainly moves several body lengths, and is still moving downwards at the end of the clip.
Anyone who lives in a mosquito heavy area knows that mosquitos (like almost all airborne insects) go into hiding during heavy rain and/or wind.
Big enough to shrug off a raindrop hit, or small enough to surf along the surface tension until it can slide off?
http://www.scientificamerican.com/article/what-do-butterflie...
Probably not 1000, but perhaps getting on for it.
I don't get it, the scientificamerican blog that they are quoting has the right units, where did they come up with this?
So if the mosquito's weight is insignificant compared to that of the heavier and denser water drop and that's what keeps it from having the force transferred, would this equally apply to hailstorms? (Where our mosquitoes are pelted by small hail balls the size of raindrops)
[1] http://www.accuweather.com/en/features/trend/hail-or-sleet-h...
http://www.local10.com/news/plane-to-spray-for-mosquitoes-ov...
Ah you mean different mechanical properties ;)
>"Why, one species even secretes an enzyme to dissolve the organic matter in blood leaving only the iron in haemoglobin. Then another enzyme causes the iron atoms to join to form biological drill pipe! These structures are known to be as much as 6 inches in diameter and to extend a mile deep."
Is there something to it or he just went to on the internet to tell lies?
The real problem is here:
> But because our mosquito is oh-so-light, the raindrop moves on, unimpeded, and hardly any force is transferred.
We have a transfer of momentum (force times time), but no dissipation of energy (force times path).
Even the transfer of momentum is much less than it would be if the mosquito were heavier though. The droplet maintains most of its original momentum. That seems to be the point they're trying to make.
> In any case, you read with exasperation or amusement the multiple errors in a story, and then turn the page to national or international affairs, and read as if the rest of the newspaper was somehow more accurate about Palestine than the baloney you just read. You turn the page, and forget what you know.
Which is of course intriguing, since cat-v.org hosts frothing-at-the-mouth vitriol about topics like women in tech and gay marriage in the always trustworthy and well reasoned medium of reposted reddit and slashdot comments. And presumably I'm supposed to click over to the technical stuff with a straight face.
cat-v is chock-full of food for thought. You don't have to agree with any of it and in fact disagreement is a large part of the site.
"Other than total and complete world domination, the overriding goal is to encourage and stimulate critical and independent thinking."
[0] http://io9.com/5916251/why-can-mosquitoes-fly-in-the-rain
I live in a mediterranean zone near a huge lake and during summer mosquitos are your every night companions (specially if you're working during late night hours). But when a summer storm brews the mosquitos disappear for two or three days. Why? This has been for me a recurrent question, and the answer has been always obvious: few of them survive being hit by raindrops.
You can make 1000 theories about how our tiny vampire friends deal with raindrops, but it's pretty clear that intensive rain (>3hours) wipe out mosquitos population for several days...
I retrieved a link to an article last year that discusses a device that uses solar power to aerate ponds as a mosquito preventative [1].
A reasonable conclusions for the drop in population is therefore that two generations can be severely depopulated by a heavy rainstorm, leaving only the portion living in stagnant water that is sheltered from the rain and run-off to survive and repopulate.
1. http://www.wired.co.uk/news/archive/2014-05/19/mosquito-devi...
> "And yet (you probably haven’t looked, but trust me), when it’s raining those little pains in the neck are happily darting about in the air, getting banged—and they don’t seem to care."
I have looked and I don't trust you. I live in Brazil where mosquitoes are present all the time, even in the city (obviously, on a smaller scale than places closer to nature). I do notice that whenever is raining there is a sharp drop in mosquitoes number flying inside our homes. They don't completely disappear, but is notorious they are in much smaller numbers. As this is common knowledge over years and years, across basically all the people, I don't consider it anecdote, but empirical observation.
I cannot answer if that is because raindrops kill them, or they just preserve themselves sheltered in their nests, or they breed less in rainy days, or whatever. But the article (not sure about the research) is based on a false premisse.
I'm guessing it still sucks for them.
Then there was the time that Pecos Bill lassoed and rode a twister, but that's a tale for another time.
Yes, Krulwich does draw pretty well.
An interesting human scale contrast is the following:
You have (a) a heavy metal box or (b) a light wooden box and you throw (1) a bouncy rubber ball or (2) an equally heavy piece of clay at it. What happens in all four combinations?
One observation: the rubber ball transfers more momentum, but almost no energy.
And compared to the equators its nearly incomparible.
I suppose raindrop vs hailstone is a reason is one of the reason's the density issues are so different.