[UPDATE: I've now extended this concept out into a mini-site. Take a look at the Through Thick and Thin site for a rough prototype. The next steps? Getting more objects, making a proper calculator … and figuring out what to do with this!]
What is the right weight of something? If it feels too heavy it’s uncomfortable, yet something that feels too light is cheap.
That was the theme of the Rightweight workshop that took place in November 2010 (I’d just arrived in the country and didn’t know about it, but wish I’d been able to attend.) Luckily there’s a book documenting the event.
One of the ideas I was most interested in was that of density. In a world of injection-moulded materials, it’s hard to get a handle on what something actually weighs short of actually looking up the weight. (I know that people are surprised at the relative weight of my 2007 Black Macbook—admittedly it’s been souped up with a bigger hard drive than it initially came with, and black is as slimming for laptops as it is for dresses).
One idea put across was what various objects would be made of were they solid instead of hollow. The authors said that based on density, an iPhone would be a literal brick, based on its density. Here’s the graph he provided (which I’ve also made into an interactive graph)
An idea I got from that was what would happen were this to be the case?
The iPhone 4
As it turns out, they were right, with a weight of 140g and a volume of about 63cm3, it comes out at a density of 2.23g/cm3 which is somewhere between brick and concrete.
An iPhone has the same density as brick
The Macbook 2007 model (the one I own):
At 2.36kg (including batteries) and a volume of 2029cm3 (2.75 x 32.5cm x 22.7cm), it comes out at a density of 1.16324 g/cm3 = somewhere among nylon/rubber/paper (literally a Macbook!)
And a Macbook is the same weight as a book
A Macbook air weighs 1.08kg and has a volume of 576cm3 ((0.3-1.7)/2 x 30 x 19.2 cm) = 1.875 g/cm3 (halfway between carbon fibre and brick).
With a weight of 140g without batteries and and 186 with 2xAA batteries and a volume of 464.209cm3 it comes out as 0.28g/cm3 without batteries (cork) and 0.376705cm3 with them (between cork and pine).
With a weight of 47g without batteries/93g with them and a volume of 42.387cm3 (11.43 cm x 5.84 cm x 1.27 cm x ~0.5 for the curvature) the density without batteries = 1.10883 (nylon/rubber) and with batteries = 2.19407 (brick/concrete)
With a weight of 23g for lithium and a volume of 7.7cm3 (0.7*2 x π x 5.3) it comes out with a density of 2.97g/cm3 ( a bit more than granite/slate/aluminium)