Those who have never stepped on Lego barefoot are not qualified to talk about life

Lego bricks are probably one of the most popular toys in the world, but the memories they bring are not always good. If you have ever accidentally stepped on those Lego bricks scattered on the ground with your bare feet, you must have found it hard to forget this unforgettable feeling. On the Internet, we can also easily find the wailing of feet that have been abused by Lego:

This is how I feel when I step on Lego:

This is a transnational pain, and someone even made a T-shirt for it:

Lego is so painful to step on that "I wish you step on Lego" has even become a terrible curse...

"I want you to step on Lego in the dark, barefoot." Image from: memegenerator.net

Even Lego itself is aware of this, and for this reason, they launched - Lego slippers...

Why can a small plastic toy building block be so lethal? Why is it so painful? Of course, we can find many universal explanations for this kind of pain: the soles of the feet are very sensitive.

First of all, like fingers, the soles of the feet are sensitive to touch and pain, which is very helpful for us to sense danger. If the feet cannot feel pain, the situation will be even worse: some diabetic patients will be very insensitive to pain in their feet due to neuropathy. They are prone to injuries and infections, but they cannot detect them in time. Sometimes the lesions even develop to the point where they have to be amputated.

You are fat (not

Secondly, you put your own weight (even with the extra force of pushing off the ground when walking) on ​​the small area of ​​​​the Lego brick under your feet, and the resulting pressure must be very deadly. If you don't consider the bulge, the upper surface area of ​​​​a 2*2 Lego brick is about 2.5 square centimeters, and a person weighing 60 kilograms can generate a pressure of 2352 kPa when pressing on it.

Of course, shape is also important, and if you add in bumps and sharp edges, the damage value becomes even higher.

What's so special about Lego? It's very hard

Obviously, the above explanation applies to all small objects that may come into close contact with the soles of your feet. So why do people always complain more about their miserable experience of stepping on Lego? Compared with other small things, what is special about Lego bricks?

It really does exist.

Of course, the fact that LEGO toys are more likely to be found on the floor is certainly a factor. However, what we are talking about here is the characteristics of LEGO bricks themselves. In short, compared with many other everyday objects that may be stepped on, LEGO bricks are exceptionally strong. They are very hard, and even if you step on them, the solid structure and sharp edges will not deform, and they will still hit your soles.

At first glance, Lego bricks seem to be just ordinary small pieces of plastic, but these plastic parts have amazing precision: they can fit each other precisely, neither too tight nor too loose. It is said that the dimensional error of these small bricks can be as low as 0.002 mm. In order to make small plastic parts have such precise dimensions, the production process and the choice of materials are very important.

The production process of Lego bricks is actually very simple. You only need to use a processing equipment called an "injection molding machine" to heat and melt the plastic into a flowable melt, then quickly inject it into a metal mold. After cooling, you can get a Lego brick.

So, what materials are used for Lego bricks? Since 1963, Lego has used a plastic called "ABS" to replace the material of the first version (cellulose acetate) to make these building blocks. ABS is one of the five most commonly used general-purpose plastics in the world. Its chemical name is acrylonitrile-butadiene-styrene copolymer, which is copolymerized by three monomer molecules: acrylonitrile (Acrylonitrile), 1,3-butadiene (Butadiene) and styrene (Styrene) (some ABS in the current process is also a blended type). Copolymerization is a common method for manufacturing polymer materials. Its advantage is that different monomers can be selected for copolymerization according to the different performance requirements of the material, so as to obtain materials that better meet people's needs.

ABS plastic particles and the three monomer molecules used to produce it. Image from: wikipedia

Why choose ABS? This is because the material properties of ABS can meet all the requirements for making LEGO bricks.

ABS is an excellent partner for the injection molding process. The styrene structure in it can bring lower viscosity to the material when heated and melted, providing sufficient fluidity for injection molding production;

The presence of butadiene structure will bring good toughness and impact resistance to the material, especially at low temperatures, the plastic will not become very brittle;

Strong hydrogen bonds form between acrylonitrile molecules, providing rigidity and hardness to the material, which also makes it more corrosion-resistant.

In addition, the existence of the copolymer structure makes it difficult for ABS material to crystallize. It does not shrink too much when cooling in the mold, so its dimensional stability is also very good. The small parts made can maintain highly consistent sizes, which is especially important for building blocks.

How difficult is it to destroy a piece of Lego? Once you understand the nature of ABS, it is not difficult to understand the pain it brings to people. The pain comes from local pressure, and there are only two factors that cause huge pressure: one is sharpness, and the other is hardness.

During the injection molding process, ABS, with its good dimensional stability, inherits the sharp edges of the Lego mold very well, so its edges are naturally "sharper". ABS has a very high surface hardness, which can reach 100 degrees Shore hardness (this is the highest level measured by this method). Super hard ABS can even be regarded as the hardest type of plastic. Not only that, the strength of these plastic building blocks is also amazing. People have done special experiments and found that ordinary 2x2 Lego bricks can withstand an average of up to 4240 Newtons of force before being crushed, which is equivalent to the weight of an object of 432 kilograms.

A Lego brick finally collapsed under the pressure of more than 4,000 Newtons - ahaha, you too! Image source: Open University

Theoretically, if you stack these small bricks one by one until the bottom brick collapses, you can build a 3.5-kilometer-high "tower". Of course, such a structure is actually very unstable, but if you use more bricks to reinforce each layer, it is no problem to build a Lego tower of more than 30 meters. In comparison, the weight of a person is nothing. Even if you stand on it, those angular and hard structures will not collapse at all.

The tallest Lego tower in the world is currently 35.05 meters high and uses about 550,000 Lego bricks. Image from: guinnessworldrecords.com

In general, the pain of stepping on Lego bricks is probably a little accident caused by the sensitive nerves of human beings and the excellent performance of polymer materials. Such an experience is definitely not pleasant, but we can also get a good news from it: your beloved Lego bricks are so strong that you don’t have to worry about breaking them by stepping on them...

Author: Why do I stand by and do nothing when the rain is knocking on my window?