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…

Australian Bird Makes Camera Shutter Sounds

By Anupum Pant

Until now I hadn’t even heard about, probably the most well-known bird of Australia, the Lyrebird. These birds are there on the 10 cents coins in Australia. Their feathers are beautiful, but what these birds can do is truly astonishing – The R2D2s of the real world.

The Lyrebird has been seen mimicking the sounds of at least twenty other birds. That’s not all. Some of these captive Lyrebirds have been seen mimicking sounds of human technology like a camera shutter, car alarm and a chainsaw too – as seen in the video below.

In 1969, as observed by an ornithologist in New England National Park, these birds were able to reproduce sounds of a flute, singing two famous songs of the 30s “The Keel Row” and “Mosquito’s Dance.”  They had learnt it from a farmer who used to play these tunes on a flute.

A word of caution

Although the video would lead you to believe that wild birds have started mimicking sounds of human technology, it isn’t totally true. The birds that has been shown in the video, in reality, are captive birds from Healesville Wildlife Sanctuary and from the Adelaide Zoo. While Attenborough makes it seem like the bird is mimicking “sounds of the forest”. these clips are not typically what these wild birds do in the wild.

Maybe it happens in the wild too, but it’s highly unlikely because the human technology sounds are usually lost amidst the forest sounds. Moreover, never in the past has there been a recording of this bird mimicking human technology sounds in the wild. Maybe they do, but science requires evidence.

Water vs. Red-Hot Nickel Ball

By Anupum Pant

Let me just not say anything before I make you watch this video today:

In the video, a Nickel ball is heated using a torch and is dropped into a bowl of water. As the hot ball touches water for the first time, it makes a certain “Ping” sound. It enters the water and gets covered in a bubble sort of thing. As it cools and the bubble is lost, that “ping” sound comes back again. The “Ping” repeats several times and is fun to hear a metal ball do that!

So much fun that the good guys on Reddit even made a couple of ringtones out of it. Download the longer one here. And the shorter one for notifications here.

Why does it form a Bubble cover?

This happens because the metal that is dropped into water is extremely hot and makes the water around it vaporize. The vapor formed around the ball acts as an insulator and doesn’t let the water touch the metal ball. This is the same effect that lets dip your hand in molten lead or Liquid Nitrogen without getting harmed by it. The same thing happens when you drop water on a hot pan – it dances.

This effect is called the Leidenfrost effect and I’ve covered it in an article before…

I’m not sure what exactly causes the “Ping” sound. If you know or have any theories, please tell me in the comments below.

CrashCourse in Quenching

Well, if I’d have wished to piss you off with jargon, I’d have said: “You just watched a hot Nickel ball being quenched in water”

Yes, quenching. Quenching is the name for making a hot metal cool very quickly. It is pretty interesting to know why some one would, with great effort, heat a metal, and then choose to drop it in water to cool off!
Cooling a hot piece of metal very quickly makes it extremely hard. So hard, that the same process is used to make the hard edges of swords that don’t get damaged even if they are used to cut metal!

There is so much more I wanted to write about the process, but I feel this isn’t the right place for it. Let me leave it for some other day.