Culture/ArtsPhysics
Archimedes’ Death Ray: Is It Possible to Burn the Ship with Sunlight and Mirror Only?
Perhaps there is an experiment we all tried when we were kids: Burning a few pieces of paper with a lens or magnifying glass. These crazy or science-loving kids usually don’t manage to burn the paper, but they can at least get it warm. Today, we’re going to talk about whether we can make a ship burn by focusing a huge lens on it. You may have thought straight up that it was impossible since we started by saying that even burning a piece of paper might not be that easy. But when the person who carried out this experiment is one of the greatest geniuses in the history of science, one might wonder “What if…?“. Let’s get started by getting to know Archimedes better first.
The First and Greatest Scientist of the Ancient World: Archimedes
Archimedes… He was a polymath born in 287 BC in Ancient Greece and is one of the most important names in the world. He is considered the first and greatest scientist of the ancient world as a result of his studies in mathematics, physics, astronomy, philosophy, and engineering. He also built the foundations of hydrostatics and mechanics.
Many people know his story of the buoyancy of water (upthrust) while he was bathing and screamed “Eureka!“. But, today we will talk about the reality of the legend of burning ships. Could Archimedes really have burned a ship using optics?
Archimedes’ Determination
Legends say, more than 2000 years ago, invading Roman fleets attacked the city of Syracuse in what is today Italy. Archimedes, on the other hand, burns the enemy ships by placing a large mirror on the rocks and adjusting the sunlight angle correctly in order to protect his city. The reflected ray is so strong that it is named “Archimedes’ Death Ray“. You can find a representative image below:
Archimedes is considered a genius whose determination cannot be questioned. As a result of his work on mechanics and levers, he once said, “Give me a lever long enough and a fulcrum on which to place it, and I shall move the world.” In fact, in philosophy, the term “Archimedean point” is used when talking about subjects that leave no room for doubt and are too definite to argue otherwise. For example, according to people who defend the philosophy of René Descartes, “cogito, ergo sum”, which means “I think, therefore I am.”, is an Archimedean point.
A Huge Parabolic Mirror
Parabolic mirrors are mirrors that are specially designed to focus sunlight on a specially selected point. In other words, they are slightly more bent than the mirrors we use when combing our hair in daily life.
(Shapes can affect not only optical properties but also durability. The article “The Science of Pringles: The Effect of Geometry on Crisp and Durability” may interest you.)
Ok, with a parabolic mirror we can direct the energy wherever we want. But we would still need a huge mirror for a reflection strong enough to set a ship on fire. This will make it very difficult for us to target a floating ship as it will limit the mobility of that mirror. Maybe we can also try using many small mirrors side by side. However, this time there should have been hundreds of people adjusting the position of the mirrors. Moreover, even in the scenario where they can all aim at the same point, a small fire will occur, which is not difficult to extinguish. Let’s take a closer look at how these experiments are done.
One of the First Experiments: A Group of Enthusiasts at MIT
As a design exercise in 2009, a group of curious students at the Massachusetts Institute of Technology (MIT) simulated Archimedes’ experiment. They were surprisingly successful. They managed to light a fake ship made of red oak by exposing it to light for 10 minutes using 127 focused mirrors. But there were a few problems with using it as a weapon.
The first problem was that many small mirrors were used instead of one large mirror. Each student had to aim at the exact same spot for it to catch fire. If one person reflects the sunlight using a mirror, the place where the reflection reaches will be brighter, but if a hundred people do this, there will be many bright areas and it will be very difficult to tell which area is the reflection of which mirror. Even for MIT students! Another problem in this experiment is that the fake ship is dry. A dry oak will catch fire faster, while it will be much harder to burn when wet. The other problem is that it takes a long time like 10 minutes for a successful flame. Even if everything goes well and full focus is achieved, it is very possible for the enemy to notice the sunlight and take precautions during this time. Do not think of anything too serious as a precaution. Even just pouring some water on that area will prolong the ignition time.
Although the curious youngsters at MIT have come to this conclusion, there is a very famous group in the world that tries to see if the myths are true: MythBusters. Now let’s see how they came to an end.
The Fear That Every Myth Will Face at the End: MythBusters
In 2010, the MythBusters team also wanted to try “Archimedes’ Death Ray“. Realizing that it would not be possible with a single mirror, the team asked 500 volunteer middle school and high school students to put a mirror in front of them and focus the mirror on a point. Moreover, instead of a large ship, as in Archimedes’ story, they aimed their beams at a sailboat that could catch fire more easily (about 500 degrees Fahrenheit). Even in the best attempt, the sailboat only warmed up to about 230 degrees Fahrenheit. This is less than half the temperature required for the sailboat to catch fire. Therefore, it has been revealed that this legend cannot be true.
So, does this method still work somehow? Yes, Jamie Hyneman, the researcher of the MythBusters team waiting inside the sailboat, concluded: Maybe the sailboat was not on fire, but the incoming rays were dazzling. It was causing all the distractions. Also, the possibility of 230 degrees Fahrenheit (about 110 degrees Celsius) rays touching your skin looked pretty scary. Thus, although this tactic did not cause a ship to burn, it could be a method for repelling enemies.
The Insidious Cause of Summer Forest Fires: Glass Bottles
Unfortunately, there is a forest fire reality that has been increasing in our world. Let’s leave the political and conscious burning aside. Let’s talk about an optical fact that many of us do not think very likely. Glass bottles can have a similar effect, just as Archimedes’ parabolic mirror focuses sunlight, causing it to heat up. In the summer months, the trees are in a drier state due to the low rainfall and high temperature. That’s why sun rays coming at a dangerous angle and for a long time can cause a tree to catch fire, as evidenced by the MIT students’ experiment. Therefore, we should definitely not leave reflective garbage such as glass bottles in forests, picnic areas, in short, any environment with trees.
References and Future Readings
2.009 Archimedes Death Ray: Testing with MythBusters. 2.009 death ray with Mythbusters. (n.d.). Retrieved July 11, 2022, from http://web.mit.edu/2.009_gallery/www/2005_other/archimedes/10_Mythbusters.html
Archimedes Death Ray: Idea Feasibility Testing. 2.009 product engineering processes: Archimedes. (n.d.). Retrieved July 11, 2022, from http://web.mit.edu/2.009_gallery/www/2005_other/archimedes/10_ArchimedesResult.html
Krystek, L. (n.d.). Archimedes and the Burning Mirror. The UNMUSEUM: Archimedes and the burning mirror. Retrieved July 11, 2022, from http://www.unmuseum.org/burning_mirror.htm
The proofreading has been done by Asu Pelin Akköse and Mete Esencan.
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