This Tiny Sponge is Probably Set to Change The World

By Anupum Pant

Background

Things absorbing water from the air is nothing new. Hygroscopic substances – or substances which have ability to attract and hold water molecules from the surrounding environment – have always been around. Coffee powder for instance is one great example – leave the dry coffee powder in the open and it will turn into a mushy matter within hours. Thanks to the moisture present in the air that it absorbs.

Hygroscopy in Nature

In the nature too, hygroscopy – the ability to extract water from thin air – has some peculiar functions. One fantastic example is the seed of the needle-and-Thread grass. This seed, with the help of a hygroscopic awn attached to it, can twist and untwist the screw like structure by releasing and absorbing moisture from the air. This way, it is able to dig its way into the ground. But that’s just one of the many examples of how hygroscopy is all around us. Here’s another one…

Thorny devil – an Australian lizard – lives in the arid scrubland and desert that covers most of central Australia. It has a hard time finding water in this dry place. So, blessed by the evolutionary forces of nature, the lizard has developed tiny hygroscopic channels between the spines on its back. These channels, working in tandem with a capillary action mechanism, are able to draw water from the air. Then their precise design makes the water move into the mouth of the lizard. Fascinating!

Other Ways

Although not exactly using hygroscopy, the Namib desert beetle, also does something similar – drawing water from thin air. Unlike the hygroscopic grooves of the thorny devil’s back, the desert dwelling beetle has developed some patterns on its hard wings which help it in drawing water from the air. These patterns include an array of  hydrophobic and hydrophilic materials which are able to trap water from the foggy morning air and are able to channel it to the beetle’s mouth.

The Nanotube Sponge Mat

This particular beetle’s hard wings with magical patterns on it, intrigued a couple of researchers. They took cue from this natural material and were able to create an artificial mat which could absorb water from the air.

nanotube sponge

Although we do have commercial Atmospheric Water Generators (AWG) which can harvest water from the air and supply drinking water, the sad thing is that these things run on electricity. This new mat that was fabricated recently, using an array of carbon nano tubes sandwiched between hydrophilic and hydrophobic layers, doesn’t need any electricity to extract water.

This mat they’ve fabricated is smaller than your thumbnail, but it still works, and is able to extract about 1/4th of it’s weigh in water within a few hours. The researchers are working on it to make it more efficient. [more information] [Original Paper]

A couple of years back a US based startup, NBD Nano, was inclined on developing a water bottle based on the same Namib desert beetle principle. The much touted water bottle, they said, would be able to fill itself! I’m not sure where their project is headed today, but an auto-filling water bottle sure would be a product just too cool to not own by every kid at school!

Needless to say, it would probably make a huge difference by lowering greatly the number of people who don’t find clean drinking water every day – Just for the record, about 1/7th of the world population didn’t have access to clean water today.

Crickets – Nature’s Weather Reporters

By Anupum Pant

Background

An annoying Cricket’s treet-treet-treet noise is really unbearable sometimes, especially when a house cricket ends up under your bed and treets all night long. To others, it’s pleasing, they associate it with the night time, and it makes them go to sleep.

Whatever it is for you, there’s one interesting thing universal about that noise they make. If you can count the number of chirps, you can almost accurately estimate the atmospheric temperature using a simple formula! Good ‘ol farmers used to do this.

I know all of us have smartphones these days, so counting cricket chirps to estimate temperature probably makes no sense to you. Still, I’ve said it back then and I say it again, it’s never bad to know anything.

Here’s how you do it

For doing it, you somehow should be able to measure 14 seconds. In those 14 seconds, count the number of times a single cricket chirps. Suppose there are 35 chirps heard, you save that number and add it to 40 (always 40). And this gives you the present temperature in Fahrenheit.

35 chirps + 40 = 75 degrees Fahrenheit

Now, since only a handful of countries use Fahrenheit to measure temperature, you might want to convert it into Celsius scale. I personally am comfortable with only the Celsius scale. But you don’t have to go through the trouble of converting because, to measure the temperature in Celsius scale using the cricket’s treet, this is what you have to do.

Simply count the number of chirps it makes in 25 seconds. Now divide the number by 3 and add 4 to it. There you have your ambient temperature in Celsius scale. Suppose the cricket chirps 50 times…

(50 chirps/3) + 4 = 20.67 degrees Celsius 

Why it works

To know that it is first important to understand how a cricket makes that sound. Remember only male crickets of a few species make this sound. They do this by a process called stridulation – rubbing 2 body parts to make a sound. Rubbing the underside of one wing with the upper side of the other wing does this trick – as they have rough and hard structures over there.

To move these wings it requires a particular chemical reaction to happen in their muscles. The speed of this chemical reaction is dependent on how hot or cold it is. The hotter it is, the faster the reaction happens and the faster it is able to move its muscles to produce more sounds in those 14/25 seconds…

via [Scientific American] and  [Howstuffworks] and [Farmer’s Almanac]

Klein Bottle – A Bottle That Contains Itself

By Anupum Pant

To appreciate the beauty of mathematics and nature there is no escaping without learning about a Klein Bottle. A three-dimensional representation of a Klein bottle looks like this – [image]

There are number of phrases you can use to describe (not exhaustively) it. A few of them are as follows:

  • An object with no boundaries.
  • An object with no inside or outside.
  • One sided surface.
  • Non-orientable surface

Wikipedia describes it as:

The Klein bottle is a non-orientable surface; informally, it is a surface in which notions of left and right cannot be consistently defined.

Simplifying things: A Möbius strip is a simpler example of a non-orientable object. That means it has no inside or outside. Add another aspect – having no boundaries – to it, it gets more complex and you end up with a Klein bottle.
If you haven’t heard of Möbius strips, to understand such surfaces, you can make one for yourself now.

  1. Tear off a strip of paper.
  2. Hold it horizontally, straight with both of the short edges in your hands.
  3. Now, twist one of the edges by 180 degrees and join the two short edges. You’ll have something like this in your hands – [image]

Test the surface and edges: On this object you just created, move your finger along the surface. You’ll find that your finger comes  back to the same place eventually. There is no inside or outside for this object, there is just one surface.
The same thing happens with its edge (try moving your finger along the edge). Here is a Music box playing a Harry Potter theme continuous – forward, inverted, forward and so on – manner; Relevant video: [video]

Now spin it (the Möbius Strip) fast. You can NOT practically do it. I mean, spinning it like you spin a circle and get a sphere. There! You have a Klein bottle. It is better than a Möbius strip in a way that it (Klein Bottle) has no boundaries.

Klein bottles cannot actually exist in our three-dimensional worlds, the ones that look like them (Klein Bottles) are just 3D representations of a 4D object. Like a two-dimensional drawing of a 3D cube. These models are available for you to buy. Interestingly, in spite of having no inside or outside, they can be filled with a liquid. But, given the opposing force of air, they are pretty tough to fill. It is important to note that the 3D representation of a 4D Klein bottle has an intersection of material, this doesn’t happen in 4D. It is like the intersecting edges of a 3D cube in the 2D representation.

You’re thinking 3D? At MIT (and other places) 4D printing is already happening.

If you are having a tough time imagining this 4D object, the following 4D animation might help (or leave you perplexed) – [video] [Extra reading for math geeks] as if they already didn’t know about Klein bottles.