December 7, 2023

Adventures of a LEGO® Cryonaut

LEGO® bricks find uses in the most unexpected places. Recently we reported on a study that examined LEGO® elements lost at sea as well as a turtle wheelchair constructed using Technic. Now, our favorite interlocking plastic bricks have done it again. However, this time they have set a world record for the coldest LEGO® bricks in the universe. Additionally, Springer Nature publications heralded the associated scientific study results as one of top 16 physics papers of 2019. True North Bricks caught up with Josh Chawner, a PhD candidate at Lancaster University, to learn about the amazing adventures of a LEGO® cryonaut.

First, let’s make clear that this experiment was born from a love for LEGO® bricks. Josh is self-proclaimed adult fan of LEGO® (AFOL).  His roots with the hobby run deep. You know you are dealing with a true AFOL when they provide you with the set number of their favorite childhood kit. Incidentally, Josh’s is 6098, King Leo’s Castle, which he got for his seventh birthday. “It was my first large set,” Josh recalls. “At school I could not concentrate on anything as I was so excited to get back home and build it.”

This experiment was born from a love for LEGO® bricks.

The LEGO® Cryonaut.
The intrepid LEGO® cryonaut (credit: Joshua Chawner).

However, Josh’s LEGO® journey began even before King Leo rode into his life. “My two older brothers got into LEGO® before I did, so I have been surrounded by LEGO® as long as I can remember. Of course, I wanted to be like my older brothers and get my own sets. I would put them together with my Dad and brothers. When I was older, I remember getting completely hooked on LEGO® and spending hours staring at the latest magazine thinking about what I would get next. Soon my taste in LEGO® sets outgrew what was available in my local toy shop, so my Grandma used to phone the LEGO® offices in Denmark to request the exact sets I wanted.”

Sadly, like many modern AFOLs, Josh eventually plunged into a dark age. Eleven years after King Leo, he went off to college and left LEGO® behind. Throughout university, he did not build. The Beatles brought him back. “When I started my PhD, LEGO® released set 21306, the Yellow Submarine. The Beatles are my favorite band of all time, so I simply had to get it,” Josh recounts. “After that I ended up treating myself to the Old Fishing Store, then the Chinese New Years sets… and now I’m an AFOL!”

“I have been surrounded by LEGO® as long as I can remember.” -Josh Chawner

Dilution refrigerator controls used to free the LEGO® cryonaut.
Lancaster-built gas handling system for the dilution fridge. This network of pipes and valves controls the dilution fridge (credit: Joshua Chawner).

Josh’s long and re-emerging history with the LEGO® brand eventually led to the adventures of a LEGO® cryonaut. You see, Josh’s PhD examines low temperature quantum electronics and electron thermometry. He conducts his research at Lancaster University in the United Kingdom. Lancaster is home to the most effective dilution refrigerator in the world. You might be asking yourself, what is a dilution refrigerator? Simply put, it is not your common household appliance. According to Josh, “a dilution refrigerator is a machine that is capable of cooling stuff down to millikelvin temperatures (around 0.001 K), and below. That’s -273.149°C!” In other words, -459.668°F for our American friends.

“One of the fastest growing uses for dilution refrigerators is the building of quantum computers,” says Josh. “In fact, over the last 10 years commercial dilution refrigerators are selling very well for this reason. Quantum electronics are very delicate systems that are sensitive to any form of energy. Mechanical energy (vibrations in the ground), Electromagnetic energy (radio waves, light, etc.), and of course, thermal energy (temperature) can all prevent these devices from working. So, a dilution fridge takes care of the thermal noise part by sending the device to incredibly low temperatures and removing almost all the thermal energy. Google, IBM, and other big names are all competing to make the most powerful quantum computer. As such, they all use dilution refrigerators to achieve this.”

A dilution refrigerator can cool stuff down to -273.149°C (-459.668°F).

LEGO® bricks being loaded into the dilution fridge.
LEGO® bricks being loaded into the dilution fridge (credit: Joshua Chawner).

The cryonaut story begins one night as Josh and an associate, Dmitry (Dima) Zmeev, were at the pub. In a twist of fate, they discovered a box of LEGO® under the table and started building. Little did the duo know, the serendipitous box and subsequent discussions would lead to a world record and a major scientific discovery. “Dima suggested to me that if I simply put a LEGO® figure in one of our cryogenic fridges then I would certainly get a world record,” Josh recalls.

In addition to his research, Josh runs Hamster Productions, a popular YouTube channel showcasing mostly LEGO® stop-motion. At publication, the channel has over 165,000 subscribers. “It just made sense to both of us to cool the LEGO® down and film the whole process for the channel,” says Josh. “Measuring the thermal conductivity of the LEGO® bricks was Dima’s idea. He showed me a paper where some researchers measured the thermal conductivity of wood. We both just thought, why not try with LEGO®?”

The idea was born at a pub over a box of LEGO®.

Josh Chawner (left) and Dmitry (Dima) Zmeev following the adventures of the LEGO® cryonaut (credit: Joshua Chawner).

Josh placed four bricks and an intrepid LEGO® cryonaut Minifigure into the dilution refrigerator. Ultimately, the experiment broke all records for the coldest LEGO® bricks. We are not just talking about the world here, but the entire universe. The dilution refrigerator is 2000 times colder than deep space. Therefore, Josh’s work certainly broke any previous records held by LEGO® sent to Mars or Jupiter. (Yes, you read that correctly. LEGO® has been sent to space.)

In addition to the new record, Josh made a surprising discovery. It turns out that LEGO® bricks are a better insulator than many high grade, expensive options currently on the market. The study published in Scientific Reports found that heat applied to the top of a stack of LEGO® bricks did not change the temperature at the bottom of the stack. “Really it was an accidental finding. We had a rough idea the results could be good, but they were much better than we expected,” says Josh. “I think the difficulty for heat to transfer from one brick to the next was a contributing factor for the insulation properties of LEGO®. This could be because the bricks have strong clutch power with very little contact internally. The design of the LEGO® bricks means much of the structure is empty space. Additionally, LEGO® is scalable, repeatable, customisable, cheap, and strong.”

LEGO® bricks insulate better than many expensive options currently on the market.

The adventures of a LEGO® cryonaut about to begin.
The adventures of a LEGO® cryonaut about to begin (credit: Joshua Chawner).

The research has already led to some interesting innovations. Inspired by the LEGO® experiment, the Lancaster team are now 3D-printing and testing solid, void (hollow) structures using ABS plastic. These structures can potentially insulate quantum computers at a lower cost than what is currently available. Josh adds, “there could be application for these insulators in space technology (outer space is around 3 K), particularly because they could be printed in-orbit!”

All this to say, LEGO® bricks have broken another record while simultaneously advancing modern physics. A Minifigure cryonaut survived the coldest temperatures known to man, and the amazing design of LEGO® bricks surprised everyone by out-competing well known brands as a cryogenic insulator. And it all arose from a childhood love for LEGO® bricks, and a couple of adults building in a pub. Not bad for the adventures of a LEGO® cryonaut.

Check out Josh’s award winning video from YouTube below:

References, links, and further reading:

“Bristol Science Film Festival award for Lancaster student.” Lancaster University, 10 June 2020, Accessed 7 August 2020.

Chawner, J. “The World’s coolest LEGO set! (Literally).” YouTube, uploaded by Hamster Productions, 23 December 2019,

Chawner, J.M.A., Jones, A.T., Noble, M.T. et al. “LEGO® Block Structures as a Sub-Kelvin Thermal Insulator.” Scientific Reports, vol. 9, 19642, 2019, Accessed 7 August 2020.

“The coolest LEGO® in the universe.” Lancaster University, 23 December 2019, Accessed 7 August 2020.

“LEGO® research among top 16 physics papers worldwide in 2019.” Lancaster University, 12 March 2020, Accessed 7 August 2020.

A very special thanks to Josh Chawner for taking part in this interview and providing the media for this article. To check out more of Josh’s LEGO® work, check out Hamster Productions on YouTube!

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