People said this experiment was impossible, so I tried it

What is thermite? (0s)

• Thermite is a chemical reaction discovered over 125 years ago that releases a tremendous amount of heat, capable of liquefying metal (7s).
• Although thermite is not an explosive, it can cause explosions due to the intense heat it produces (14s).
• The reactants in thermite are extremely inert, allowing them to withstand a blow torch indefinitely (25s).
• Thermite has been used in Hollywood to create special effects resembling a nuclear bomb, as seen in various films (34s).
• In its most common use, thermite has remained largely unchanged for over a century and has played a significant role in helping move billions of people worldwide, likely referring to its use in railroads or other transportation infrastructure (42s).

Hans Goldschmidt and the first thermite reaction (51s)

• In the late 1800s, Karl and his younger brother, Hans Goldschmidt, studied chemistry under Robert Bunsen to prepare for joining their family's chemical factory business, which produced dyes for fabrics (55s).
• After their father's early death, Karl took over the company, and Hans later joined him, with one of Hans' primary research goals being to find a way to produce pure metals, essential for making dyes (1m17s).
• At that time, good dyes were hard to come by, and most were faint and faded further after use, with some requiring the collection of large quantities of exotic insects (1m30s).
• The demand for pure metals was strong, particularly for colors like Scheele's green, a toxic copper arsenite dye, and the red color of British Army officer's coats, made from cochineal, a central American insect mixed with tin (1m52s).
• Hans and his brother had experience purifying metals by dissolving them in solutions or acids and working with salts, but this process had its problems, including reducing the salts in a furnace and dealing with contamination through carbon (2m29s).
• Hans came up with a novel idea to react a metal oxide like chromium oxide with aluminum metal, hoping the oxygen would swap partners, forming aluminum oxide and pure chromium, now known as an aluminothermic or thermite reaction (3m19s).
• To replicate Hans' first successful reaction, an experiment was conducted using copper instead of chrome, with 300 grams of thermite poured into a crucible and ignited, releasing a lot of energy and reaching temperatures exceeding 2,000 degrees Celsius (4m10s).
• The reaction released a lot of energy due to aluminum forming strong bonds with oxygen, melting the products of the reaction and making them glowing hot, with the resulting liquid copper being visible at the bottom of the crucible (4m57s).

The reaction as it’s never been seen before (5m55s)

• An experiment is being set up to separate pure metal and aluminum oxide from a hot mixture, using a crucible cut in half with thermally resistant glass attached as a window to observe the reaction inside (6m6s).
• The glass has been specially treated to prevent it from shattering immediately when it comes into contact with molten metal, but it is expected to melt slowly due to its lower melting temperature of around 1,700 degrees Celsius (6m39s).
• The experiment uses iron thermite, a combination of iron oxide and aluminum metal, and the reaction is ignited, causing the mixture to expand outwards in all directions (7m30s).
• The reaction appears to be pulsing, with a series of bursts and pauses, and it is suggested that this may be due to gas escaping and creating space for the next burst (8m31s).
• The pulsing reaction is also observed to resemble the movement of ants or mold, and it is noted that this behavior has not been seen before in thermite reactions (8m23s).
• To get a closer look at the reaction, thermite is placed on top of glass and filmed from below using a probe lens, capturing the closest footage of a thermite reaction ever taken (9m25s).
• The footage shows that the reaction proceeds in bursts, reacting quickly and then pausing before advancing again, and two possible explanations are proposed for this behavior: the mixture of grains needing to be in the right ratio to react efficiently, and the expansion of air between the grains increasing the pressure and pushing unreactive material away from the reaction front (10m6s).
• Once the air escapes from the thermite reaction, the next patch can ignite, and after all the thermite has reacted, molten metal is ejected out of the top of the crucible, and the liquid inside starts sloshing around due to some materials boiling (11m14s).
• The boiling point of aluminum is around 2,500 Celsius, iron boils above 2,800 Celsius, and other elements in the mixture like manganese boil at just 2,000 Celsius (11m41s).
• After the boiling stops, the liquid settles down, and the key to making pure metal is that the density of liquid iron is more than twice that of liquid aluminum oxide, causing iron to settle to the bottom and aluminum oxide to float to the top (11m57s).
• When the metal melts through the bottom of the crucible, the first liquid to pour out is iron, followed by the aluminum oxide or slag, which can be visually distinguished due to their different viscosities (12m18s).
• The experiment demonstrates the separation of iron and aluminum oxide, with iron having a viscosity like water and the slag being smoother and more like warm honey (12m35s).
• A camera is used to capture the experiment, including the flames and bubbles on the glass, and it continues to record even when on fire (13m13s).
• A cobblestone made of limestone is placed inside the crucible, and after the thermite is ignited, the cobblestone rises to the surface due to its lower density, similar to the slag (13m30s).
• The separation of denser metal and less dense rocks or slag is key to producing high-purity metal in the crucible, a process developed by Hans Goldschmidt (14m8s).
• Hans Goldschmidt patented the process in 1895 and wrote about its simplicity and extraordinary effects, noting that thermite was a solution looking for problems (14m34s).

How thermite welding works (14m57s)

• Thermite was initially used to weld metal parts in remote locations where a strong and reliable weld was required, and it was not feasible to bring heavy equipment and welding gear (14m57s).
• One of the first customers for thermite were shipping companies, which used it to fix broken shafts in the middle of the ocean, allowing them to return home safely (15m18s).
• Thermite was also used to fix cracks in engine blocks and was valued for its mobility, as it only required two people and a bucket to operate (15m38s).
• The iron thermite used in welding does not produce pure iron, but rather steel, by including carbon and other alloying elements in the thermite powder (15m49s).
• Pure iron is not useful due to its softness and tendency to corrode quickly, so the majority of thermite produced today is steel thermite (15m59s).
• After the Cold War, thermite was used to destroy obsolete or captured military equipment, such as gun barrels from tanks, by welding them shut and rendering them useless (16m25s).
• Thermite is also used to destroy information stored on magnetic hard drives by heating them above the Curie temperature, at which point the magnets lose their magnetism and the data becomes unrecoverable (17m0s).
• Modern thermite can take different forms, including a dry, tile-like material that can be handled safely (17m21s).

I destroyed a laptop! (17m43s)

• An experiment was conducted using a thermite tile to destroy a laptop and its hard drive, with the goal of rendering the data unrecoverable (17m45s).
• The thermite tile was ignited in all four corners, generating heat for about 10 minutes and causing the laptop to melt and release molten metal (18m8s).
• The temperature and reaction rate of the thermite were controlled to make the process slower and more contained, rather than explosive (18m2s).
• The experiment was successful in destroying the laptop and its data, with the molten metal forming a puddle and the laptop's logo being visible in the thermite (19m4s).
• The experiment was sponsored by Incogni, a company that helps protect individuals from data brokers by removing their personal information from the open market (19m40s).
• Incogni works by identifying which data brokers have an individual's information, determining which laws apply, and sending requests to remove the information (20m21s).
• The service is easy to use and has been effective in reducing spam calls, with the ability to continuously protect against data brokers in the background (20m36s).
• Thermite is not well-suited for use as an explosive due to its inability to produce a rapid release of energy and pressure (21m26s).
• The controlled nature of thermite reactions makes them interesting and important, allowing for precise calculation of energy release but not pressure or time (21m35s).
• The thermite reaction can be carefully controlled, allowing for applications where conventional explosives would cause too much damage, such as the removal of the burnt-out steel dome of the Reichstag building in Berlin in 1957 (22m48s).
• The thermite mixture can include pieces of pure steel that absorb heat as they melt, helping to control the rate of reaction and the temperature reached (23m17s).
• The tap time, or the time it takes for the metal to start flowing out of the crucible after the reaction starts, is a critical parameter to control, as it affects the separation of the metal from the slag and the temperature of the metal (23m58s).
• If the tap time is too short, the metal inside doesn't fully separate from the slag, but if it's too long, the metal dissolves more silica from the walls of the crucible and comes out colder than it could have been (24m4s).
• The chemistry of the steel changes over time, making it important to control how long it stays in the crucible (24m18s).
• An experiment was set up to test whether the time when the steel comes out of the crucible can be controlled, with three crucibles ignited simultaneously to see which one would produce steel first (24m39s).
• The experiment showed that the steel can be controlled to come out of the crucibles at different times, with the first crucible producing steel the fastest (25m5s).
• Another attribute that can be controlled is the temperature of the metal, with different versions of the thermite mixture producing metal at different temperatures (25m42s).
• An experiment with two different versions of the thermite mixture showed that the temperature of the metal can be controlled, with the 12% version producing metal at a lower temperature than the 25% version (25m45s).
• The temperature of the metal can be dramatically changed in both directions, with the ability to produce metal at significantly lower temperatures (26m31s).
• The process of making thermite begins with carefully adjusting the thermite mixture (26m40s).
• This adjustment marks the starting point of the thermite-making process (26m43s).

How thermite is made (26m44s)

• Mill scale, a mixture of different iron oxides, is a waste product from the steel rolling process, where the surface of the steel oxidizes quickly due to high temperatures and water involvement, creating a layer that is then blown off with water jets (26m52s).
• The mill scale is collected, dried, and separated into different sizes and compositions before being mixed with aluminum powder to make thermite (27m48s).
• Both the iron oxide and aluminum powder must be very dry, as water can interfere with the thermite reaction, and the elements must be controlled to ensure the desired reactivity and chemical qualities in the resulting steel (28m11s).
• The thermite mixture is bagged up individually into portions, which are then stored in a warehouse, with the portions being the standard unit of measurement for thermite (28m32s).
• The warehouse storing the thermite is designed to be safe, and the thermite is not easily ignitable, as demonstrated by a test where increasing sized ignition sources were used to try to ignite a full crucible of thermite (29m22s).
• The test, which included using a lighter and a bigger torch, showed that the thermite would not ignite even when heated to the point of glowing orange, with the person conducting the test wearing a fireproof suit as a precaution (30m14s).
• The people involved in the test, including Axel and Christof, were confident that the thermite would not ignite, with Christof stating that he was 95% sure it could not be ignited (29m48s).

Blow-torching thermite to show how reactive it is (31m11s)

• Thermite is being torched to demonstrate its reactivity, with an initial temperature reading of 500 degrees Celsius (31m28s).
• The temperature increases to 700 degrees Celsius, and despite the high heat, the thermite does not ignite under normal conditions (31m41s).
• The thermite can melt without igniting, and this is due to the aluminum powder being covered in a stable layer of aluminum oxide (32m39s).
• The aluminum oxide layer acts as a barrier that prevents the reaction from starting, and it requires violent heating to break down the layer and initiate the reaction (32m42s).
• The reaction has a high activation energy, making it impossible to start with a lighter or propane torch, which is why barium hydroxide igniters are used (33m1s).
• Barium hydroxide igniters, similar to those found in sparklers, can generate enough heat to break through the aluminum oxide layer and start the thermite reaction (33m10s).
• The ignition temperature is set high to ensure that the thermite can only be lit deliberately, and once it's ignited, it cannot be stopped (33m27s).
• A demonstration of the thermite reaction is shown, with the thermite exploding after being ignited (33m42s).
• Future videos will explore how thermite reacts with its environment and its common application in welding railroad tracks together (34m0s).
• It is likely that many people who watch the video will have ridden on a train with tracks welded together using thermite (34m16s).