sand – Awesci – Science Everyday

The Underwater Vacuum Cleaners

By Anupum Pant

If you didn’t know, most white sand you see on some beaches around the world, has at some point in time, passed through a fish called the parrot fish. It’s an amazing ecological role the parrot fish plays.

An interestingly similar ecological role is served by a marine animal with a very leathery skin called the sea cucumber. Professor Ove Hoegh-Guldberg explains why these organisms have such an important role in the marine environment.

Basically, while scavenging for algae or minute aquatic animals, sea cucumbers ingest a lot of sand. As it passes through their bodies, the digestive system increases the pH of the sand, making it more basic. When this comes out, the sand is clean and turned basic. This way it plays a chief role in countering the negative effects of ocean acidification.

It also helps coral reefs survive by supplying them with calcium carbonate (a by product of its digestion process) and helping them maintain a net inflow of calcium carbonate.

The ammonia that comes out also makes the bed more fertile, making it much more suitable for coral reefs to grow.

Watch these underwater vacuum cleaners in action below.

Singing Sand Dunes

By Anupum Pant

I cannot say why you’d do it, but suppose you were on a hike to the top of a 120 feet sand dune in the centre of some desert, say near Al-Askharah, a coastal town in Oman. Unfortunately, it’s also the mid summer time, with 50 degree Celsius winds blowing at 50 miles an hour, and the dune you are climbing has a slope of 30 degrees. There’s nothing else (besides sand) to be seen or heard for miles around you.

The numbers are apparently perfect for a very eerie phenomenon to occur. And then the whole desert suddenly cries out a booming chorus of a very low hum (Like someone playing a very low note on the cello). What could have possibly caused that?

For ages such sounds in the midst of empty deserts have been bewildering people. Marco polo mentioned it. Charles Darwin also wrote about the “Bellower” in The Voyage of the Beagle. Moreover, until recently, even modern scientists weren’t sure what caused these sounds. It was only during the year 2009 that things started becoming clear when a group of researchers started experiments with sand on an incline in a laboratory environment.

The low droning hums, now as we know, come from within the sand dunes. The Sand particles are blown by the wind, causing an avalanche. As the sand falls across the 30 degree incline of the dune, they vibrate, synchronise and send the vibrations into the dune. The dunes pick up these tiny synchronised vibrations and amplify them, causing the low droning hum; coherent enough to resemble musical notes.

This only happens at few places around the world. In Morocco the dunes cry out an echoing hum of 105 hertz. Whereas in Oman the sands create a mixture of frequencies ranging from low 90 to slightly less low, 150 hertz. Something similar is also heard in the death valley. The video explains…

Sea Glass – Is It Trash or What?

By Anupum Pant

In the Glass Beach, a beach in MacKerricher State Park near Fort Bragg, California, like the name tells you, you’d normally find too many glass pieces on the beach. These glass pieces that people often find in beaches like these, aren’t exactly those sharp shards of glass that are sharp enough to harm you. Rather they are physically and chemically weathered pieces of glass – round and small.

This type of glass is called sea glass and has been a fancy of those hobbyists who like collecting these pieces to make beautiful adornments.

This kind of glass, often found on some beaches usually starts as shards of broken glass from dump or other such sources. In about a span of 1-2 years, the tumbling and weathering makes these pieces smooth and rounded. And then they are collectively known as “genuine sea glass”

At this particular beach in California, the beach glass that has formed over the years, first started coming in when residents who lived close to the beach started dumping garbage into the beach. Local clean up services tried to clean up the mess, but most of it had already gone in for natural weathering by that time.

Soon after the clean-up services came around, the beach became a great place for hobbyists to collect these naturally weathered beautiful glass pieces. All the trash that was first thought to be a mess, now became a tourist attraction – Naturally weathered genuine sea glass was a thing of natural beauty now. And then this smuggling of sea glass by tourists had to stop. First the mess had to stop, now the mess being taken away by tourists had to stop.

And once the glass has started to go away, now there is a move to replace all the glass – that was once considered garbage!

[Read more]

Chladni Figures

By Anupum Pant

If you take a surface, membrane with a layer of loose particles or certain liquids on it, you’ll see that these particles get arranged in beautiful patterns if the membrane is made to vibrate with varying frequencies.

This phenomenon has been known for a long time now, probably since the time when early human tribes used to put grains of sand on drums made of taut animal skin. Since then Leonardo Da Vinci and Galileo Galilei have been known to have observed this phenomenon by hitting or scraping a surface covered with visible particles and .

Later, with information gleaned from Galileo’s and Leonardo’s notes, in the year 1680, Robert Hooke, English scientist from the Oxford University, devised a simple equipment which demonstrated this effect much clearly. He made a glass plate covered with flour to vibrate with the help of a violin bow. And observed beautiful patterns.

Much later, Ernst Chladni explained these figures using mathematics, spread it all across Europe and made a lasting impression on The French Academy of Sciences. These patterns thus came to be known as Chladni figures.

Brusspup, a YouTube channel known for it’s amazing videos demonstrates these Chladni figures on video.

Today, this study, which makes sound and vibration visible to the naked eye, is called Cymatics.

The Hottest Place on Earth – Not Death Valley!

By Anupum Pant

For years I’ve known that the death valley was the hottest place on earth. Of course, not counting the lava, laboratory furnaces, hot springs and other such smart-ass answers, the death valley has always been, in textbooks and beyond, the hottest place on our planet.

On July 10th 1913, the temperature there was measured to be around 56.7 degrees centigrade. Nowhere else has the mercury risen to such high levels since then. Or so we thought…

Until, like always, a science channel from YouTube – MinuteEarth – decided to dive in a little deeper.

This is what the weather statistics do when they measure the temperature – The temperature outdoors are measured in shade at about 1.5 meters above the ground. Of course they had a standard procedure set to do that, and there must be a solid reason for that.

But, practically, who are we kidding. Anyone who has been on a beach, barefoot on a sunny day knows how hot the surface of sand can get in the sun, right?

The data from NASA’s satellites equipped with spectroradiometers has a different story to tell. A place somewhere in the Lut desert in Iran is the winner. The temperature averaged in a 1 square kilometre by the satellite shows that temperatures here have reached a whooping 70.7 degree Celsius. The place is somewhere inside the blue circle I made on Google maps.

You could literally cook eggs in the open there. Anyway, that isn’t totally new. Mr. Sargunaraj claims to have cooked an egg on the streets of Tirunelveli District in Tamil Nadu, India too. And I’ve also seen a video of a restaurant serving eggs cooked in the open (without fuel).

White Sand is Mostly Parrot Fish Poop

By Anupum Pant

Walking on the sparkling white sand on a sunny beach in Hawaii, sounds wonderful, right? Who’d even think, the white sand on Hawaii beaches, which people love walking on, is actually something that is excreted by a certain kind of fish called the Parrot fish…at least most of it – about 70% of it is poop.

Now, I suppose people walking on the beach must be all grossed out. But they shouldn’t be. It isn’t too bad after all. The sand (poop) doesn’t even smell like anything bad. It looks and feels completely fine. There’s actually no reason to be grossed out.

This is how it works…

The Parrot fish spends most of its time eating sea weed and polyps which grows on coral most of the time. When it tries to puck it off, thanks to the protruded mouth of a parrot fish, it scoops off a part of coral too. The coral and sea weed mixes and gets crushed in its throat.

The sea weed and polyps eventually get digested, while the crushed coral comes out as it is. As a result, it poops out the undigested crushed coral.

Interestingly, in the process of taking off a chunk of coral and munching it, the parrot fish does two good things.

Firstly, it helps the coral in removing all the parasites and other things growing on it. The fish is considered to be a natural cleaner of corals. Had there been no parrot fish, corals would have died.

Secondly, the parrot fish does a great service to its own beak in this process. As a result, the beaks don’t grow too much.

The parrot fish eats a lot, and each one of them can produce about 100 kg of “sand” every year. It has been confirmed by scientists that about 70% of the sand that is present on all the tropical beaches has come out of the back side of a parrot fish at some point of time.

This is what a parrot fish looks like and this is how it poops out sand…

Bonus fact: Our planet is old and fresh water is less. So, it’s valid to say that all the water molecules that are there now have passed through something really bad, and there’s a high chance that all of it has passed someone’s urinary tract at some point.