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Every building material has a theoretical limit which it can’t be used beyond: at some point, the weight of material above is enough to crush what’s below. Now, a team of engineers has worked out that limit for Lego — and it’s surprisingly high.
A team of researchers from the Open University decided to settle speculation — including burning debates on Reddit — by tackling the question scientifically. Here’s how they did it.
To work out how high a tower can be before it crushes itself, you need to know two things: the mass of material, and its yield strength. The yield strength describes how much loading a material can take before it begins to deform.
To work that out, you need a fancy device called a hydraulic testing machine. So, the engineers took their test specimen — a 2×2 Lego brick — and placed it into device. Then they ratcheted it up until things started getting interesting. They sailed past 350kg and wondered if they were doing something wrong. Eventually, the load reached 430kg and the brick began to slowly deform — which is known as plastic failure.
It’s not loud, it’s not dramatic, but it was definitely the end of the lego brick, as you can see in the picture: it’s squashed completely flat. Repeat experiments confirmed that the average 2×2 brick, each of which is made of ABS plastic in Lego’s factories, can take 430kg.
Once you know how much load a brick can take, then working out how tall you can build a tower is fairly easy. A normal 2×2 Lego brick weighs just 1.152g. From that, you can work out how many you need to create the whopping 430kg that the brick at the bottom of a tower could take.
To save you jumping for a calculator, turns out that figure is 375,000 bricks. You could pile 375,000 2×2 bricks on top of each other before the one at the bottom was crushed like in the experiments. Multiply that number by the height of the brick — which is 9.6 millimetres — and you realise that you could, theoretically, create a tower 2.17 miles high before anything went wrong.
It’s also worth bearing in mind that clever Lego builders have a bunch of techniques at their disposal to create taller towers by minimising mass, and the researchers even believe that 1×2 bricks would likely withstand more. So in theory, an even taller tower could be made.
That is, however, all theory. In reality, crafting a 2 mile-tall tower would be virtually impossible: in real life, the loading wouldn’t be perfectly equal or symmetric, so a tiny flaw in the structure would be massively amplified. Sorry. [BBC]
Image by BBC, Open University and Sami Niemelä
Mythbusters: the myth is that you can build a Lego tower over 2 miles high!
Well we should start with a scaled test just to see if this is possible, and then go FULL SCALE!!!!!!
I suggest we start petitioning their website
lego space elevator?
Bet you could up that a bit if you started with flat bricks before moving to the full size ones.
Jack and the Lego-stalk !
I think this is what they call “bad science”. Completely impractical and utterly unstable. The slightest puff of air and the whole unstable thing would fall over; even after a few meters.
This just proves what a load of crap most science is.
This “experiment” took maybe twenty minutes, and in the process educated people on this principles of material testing and yield strength.
Seems reasonable to me.
Nobody suggested doing it, the people behind this stated exactly what you did in their findings (but without the 6 foot pole up their arse), and you’ve totally missed the point.
Impractical yes (in this context), usefulness debatable, fun fact yes.
Science is never crap, the application of science might be though, but that’s down to humans.
Structural testing of materials does have real world uses after all.
Plus it would make a great school Math problem.
Am I the only one who heard this from the horses mouth so to speak by listening to Material World last Thursday on Radio 4?
What about the weight that we apply to the bricks when adding each brick? Wouldn’t that cause the plastic to break before 375K?
Only if you were adding bricks to the top instead of the bottom.
*Challenge accepted*