Tidbits #7 - Heavy breathing

If we could make a close-fitting cylinder large enough to encase the Eiffel Tower, the volume of air within would weigh more than the tower itself. 

And the Eden Project’s Humid Tropics ‘Biome’ in Cornwall, despite being high enough to hold the Tower of London or eleven double-decker buses stacked on top of one another, weighs around the same as the volume of air contained within it. 

We don’t think of air having weight but, of course it does. If you blow on your hand you can feel it. And while we're on the subject of breathing, did you know that your next inhalation will contain a small amount - around 20 molecules of air - of Cleopatra's dying breath?

Our atmosphere contains 1.6 x 1044 atoms, and each breath we take consists of 8 x 1022 atoms. To get some sense of that last number, if each of those atoms of air were a grain of sand, every breath you took would cover the entire United States to the depth of an eight-story building. Dividing the number of atoms in the entire atmosphere by those in one breath shows that about 1 in every 2 x 1021 atoms we breathe in the air right here is from Cleopatra's dying exhalation (assuming that winds over 2000 years have done a thorough worldwide mixing job). So each of us inhales about 40 atoms from her last gasp with every breath we take. In fact, it's probably safe to say that each breath you take includes air that passed out of the lungs of everyone who has ever lived - although the chances are increased the longer ago that they died (to allow time for worldwide scattering).

Air is made of gases and gases are made of atoms. Anything that has mass has weight if it exists within a gravity field. Atoms have mass, albeit a very small amount. And so do the component parts of atoms, such as electrons, so they can be weighed. 

In 2007, Harvard University professor Russell Seitz asked himself the question, ‘If energy is made of electrons and electrons have mass, how much does the internet weigh?’ Of course, he wasn’t including the infrastructure of the internet – the cables, servers, silicon chips, wires and cables etc. – but only the data itself. He calculated that the weight of all the electrons in motion that make up the internet at any one moment is equivalent to around 50 grams or 1¾ ounces or the equivalent of a decent-sized strawberry. And yet, to drive that 50 grams around the world, it takes the equivalent of a staggering 50 million horsepower. 

Another scientist, Prof John Kubiatowicz of the University of California, Berkeley, recently suggested that a fully loaded electronic book reader weighs more than an empty one. Each e-book is about as heavy as a single molecule of DNA. 

So, filling a 4GB reader to its storage limit would increase its weight by a billionth of a billionth of a gram (0.000000000000000001g) or the weight of a small virus.

A bit of light reading?