The Strength of Lego


Capped and Uncapped (2×1 brick) Lego specimens before compression tests

Had an absolute grand time crushing Legos with Hailey Todd and the virtual ventures summer camp at Carleton University this week. Thought Id pass on some of the results we observed. Unlike the previous study conducted for the BBC where only one Lego block type was tested, we really wanted to understand what happens with Lego under a realistic building configurations and loading scenarios. So we took typical Lego blocks of 1×1, 1×2, 1×3 and 1×4 brick sizes and tested them in a loading actuator with compressive displacement control (mm per minute).

What we observed was that as the size increased so too did the ability to carry load (see graph below). Though it was not proportional to the added stud-brick for each block. We did not cap the Legos because we wanted to see the full effect. Basically the failure mechanism is as follows, the test begins with load being applied and the Lego brick ‘stud’ is pushed into the block giving a flat loading surface along the top of the block, there is a small elastic phase and then we begin to crush the Lego block (its peak load). Later we did cap the Lego and saw some interesting differences in peak load and failure pattern (see below).

lego results

Elementary school students as part of the virtual ventures summer camp at Carleton crushed Lego to introduce them to how building materials behave under load. An unexpected non-proportional trend in load increase with brick area increase was observed.

We opted to use Lego as a teaching example as its a relatable building material to youths. I think its a gate way to show them just how strong materials are when you can relate them to the day to day lives, obviously we get them hooked there, and progress to crushing concrete and breaking steel much after.


After testing the 2×1 brick Lego. The uncapped Lego failed at 4.2 KN; whereas the capped lego failed at 3.7 KN. Both blocks terminated with the same deformation level in mm. Not the different failure mechanisms are because the load is applied differently throughout the lego.

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