The Flawed Measurement that Almost Killed Indiana Jones

Indy enters a temple laced with ancient mechanical traps, and then…


Raiders of the Lost Ark, Back to the Future and Apollo 13 are among the all-time best examples for use of measurements in a film … but that won’t stop science-minded individuals from nitpicking some of the details.

A Lego version of Indiana Jones is posed holding a cup representing the Holy Grail.
This version of Indiana Jones looks like he belongs in our Lego Kibble Balance! Credit: Willrow Hood/Shutterstock

By Ben P. Stein, managing editor in the NIST Public Affairs Office

Many critics and movie fans alike name 1981’s Raiders of the Lost Ark as one of the best films of all time. But watching the movie as a 12-year-old, I didn’t realize that it has what some consider to be a major flaw, pointed out in a 2013 episode of The Big Bang Theory. As the argument goes, Indiana Jones, the main character, made no difference in the outcome of the film. With or without him, the movie would play out the same: The Nazis would have found the Ark of the Covenant and opened it, triggering their demise.

While Indy’s effect on the plot has now become the subject of endless internet debate (what hasn’t?), I can still hold onto one fact as a proud NIST employee. Measurements play a key role in the plot — with one inaccurate measurement nearly killing Indy.

I’m talking about the scene at the start of the film in Peru, where Indy enters a temple laced with ancient mechanical traps. Indy wants to steal a prized golden idol sitting on a pedestal at the center of the temple. But he knows that taking the idol is likely going to activate a deadly trap.

When he reaches the pedestal, Indy takes out a small bag of sand, eyeballs it in relation to the idol and dumps some grains from his bag. He grabs the idol and immediately places the bag on the pedestal. At first, it looks like the swap worked, and Indy smiles in pleasant surprise. But a moment later, the bag of sand sinks the pedestal, causing the temple to self-destruct. Indy runs for his life.

I’ve never seen a better illustration of the importance of accurate mass measurements, which can indeed have life-and-death consequences in the real world. Accurate mass measurements enable patients to receive the right amount of medicine and help engineers design jet turbines and rocket engines that produce adequate thrust to deliver passengers and payloads. I think the makers of Raiders of the Lost Ark inadvertently created one of the most entertaining ways to deliver this point home to the general public. Milligrams (and sometimes even nanograms) matter!

Two “Admit One” movie tickets are tucked into the top of a paper bucket of movie popcorn.
You may be watching an award show for movies this weekend, but before that, take a trip to the movies with NIST and learn how measurements give some classic films key plot points. Credit: Carolyn Franks/Shutterstock

Later in the movie, measurements play an even more critical role in the plot, as Indy and the Nazis vie to find the legendary Ark of the Covenant. To do this, Indy obtains the headpiece to the Staff of Ra from co-adventurer Marion Ravenwood. By taking the staff to an archaeological dig site in Egypt, and placing it in an ancient map room, he hopes to see sunlight pass through a gem in the center of the headpiece and point to the exact location of the ark. However, the staff itself is missing. The headpiece indicates that the height needs to be 5 kadams, an ancient measurement unit. Indy’s collaborator Sallah estimates each kadam is about 12 inches (about 30 centimeters). They create a staff with a height of 5 kadams (presumably 60 inches) and place the headpiece on it.

This leads to a measurement goof that’s hard to explain away, even in the fantastical world of the movie. Indy is shown holding the staff, and he appears to be roughly 80% of the staff’s height. But if the staff is a height of 5 kadams (60 inches, about 1.5 meters), that would indicate that he shrunk to about 4 feet (1.2 meters) tall! (Unless they corrected their error in a deleted scene — one can only dream of a NIST Director’s cut of the movie!)

You probably never want to see another movie with us by now, but I hasten to add that the Staff of Ra scene serves the storytelling perfectly. It shows how the protagonists’ care for measurement and accurate interpretation of ancient writing provides the correct answer. What better message could there be for budding scientists?

In case you were wondering, the kadam (also spelled as “qadam”) is indeed an ancient measurement unit that was used in South Asia and the Middle East. NIST research librarian Keith Martin told me the word translates as “to walk” or a “footstep” or a “foot,” with a wide range of values corresponding to these different meanings, and it even evolved in some places to mean the distance covered in many hours of walking. “Ah, the fun times before standardization,” Keith said.

Back to the Future

Of course, Raiders of the Lost Ark is not the only movie that uses measurement in its plot. 1985’s Back to the Future is where many of us (including my 16-year-old self) first heard the word “gigawatt” (which means a billion watts). According to Doc Brown, 1.21 gigawatts was the amount of power that he needed to deliver to his juiced-up DeLorean sports car to travel through time, at a speed of 88 miles per hour. Of course, these are made-up numbers, but they communicate to the audience that exact measurements — determined through mathematical calculations and scientific and engineering considerations — are often used to perform impressive tasks. Doc Brown reinforces the idea that science is powerful and cool.


In the film Moneyball (2011), baseball general manager Billy Beane relies on statistics based on exhaustive measurements of baseball players’ performance. Beane uses this information to make key decisions on which players to add to the roster and what to do in critical game situations.

Based on a true story, the film (and book of the same name) shows the major influence of statistician Bill James, whose field of sabermetrics (based on the acronym for the Society for American Baseball Research, or SABR) has revolutionized the game.

What amazes me is how well baseball fans know and understand these often-intricate statistics, whether it’s WHIP (walks plus hits per innings pitched) or wOBA (weighted on-base average). I think the movie helped communicate the power of measurements to help sports teams succeed.

Apollo 13

Historical photo shows three returned Apollo 13 astronauts posing for a photo op with an aircraft carrier in the background crowded with well-wishers.
Apollo 13 astronauts Fred Haise, John Swigert, and James Lovell safely touched down in the Pacific Ocean at the end of the ill-fated mission. The correct measurements played a key role in bringing the astronauts home safely after their oxygen tank exploded. Credit: Courtesy of NASA

Measurements play a critical role in Apollo 13 — both in the movie and in real life. Based on the ill-fated 1970 Moon mission, the 1994 film tells the story of astronauts trying to safely get back to Earth after an electrical explosion causes their spacecraft to lose its oxygen supply.

Bereft of oxygen, the astronauts are exhaling carbon dioxide — with the buildup of CO2 threatening to poison and kill the crew. Keeping track of the cabin’s CO2 levels helped the crew and mission control to figure out how much time they had to improvise a solution to their problem — and provided suspense for movie viewers as the astronauts raced against time ultimately to return to Earth. (Some cross-movie trivia: Katherine Johnson, one of the real-life mathematicians portrayed in Hidden Figures, did work that helped the Apollo 13 crew navigate back to our planet!)

Star Wars

In the original 1977 Star Wars movie, Han Solo brags that his ship, the Millennium Falcon, is so good that “it made the Kessel run in less than 12 parsecs!” The problem is that the parsec is not a measurement of time but distance. To find out how this initially problematic measurement was resolved in the Star Wars universe, check out my earlier blog post on quirky measurement units.


J. Robert Oppenheimer, in a black and white photo, peers into the camera while holding a pipe in his mouth. Smoke billows out from the pipe.
J. Robert Oppenheimer was a physicist and known as “the father of the atomic bomb.” Credit: National Portrait Gallery, Smithsonian Institution; gift of George R. Rinhart

Some people have asked me about 2023’s Oppenheimer.

I’d say that the movie mainly showcases calculations, which are a little different from measurements. To make a measurement, you use a technique or tool such as a tape measure to directly determine the value of a property such as the height of a door.

A calculation uses formulas or other mathematical tools to obtain values of the quantity of interest, such as the amount of energy in a nuclear detonation. (There are lots of important calculations in many movies — such as Hidden Figures and The Martian — and that could be a great sequel for this blog post!)

Calculations often use measurements but are a little different from measurements themselves. Perhaps the closest thing to a measurement in Oppenheimer was a fictional addition — Oppenheimer adding marbles to a bowl throughout the film to represent measurements of how much uranium had been refined at the various Manhattan Project facilities across the U.S.

So there you have it — our nominees for best use of measurements in movies. Can you name any other movies in which measurement is an important part of the plot? Which movie do you think should be the winner? Let us know in the comments!

This article is from the National Institute of Standards and Technology (NIST), a federal agency that promotes U.S. innovation and industrial competitiveness by advancing measurement science, standards and technology in ways that enhance economic security and improve our quality of life. Find out more about NIST and subscribe to the Taking Measure blog.



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NIST promotes U.S. innovation by advancing measurement science, standards and technology in ways that enhance economic security and improve our quality of life.