Can you actually swing from spider silk?
Veritasium
The swing test setup 0:00
Henry opens by explaining that he has gathered the largest amount of spider silk ever assembled for a test like this, and he wants to find out whether it can actually hold a person's weight the way Spider-Man's webs do in the movies. He points to the scene in Spider-Man Two where Peter Parker stops a runaway train using webbing, and notes that real spider silk is reportedly stronger than steel and ten times tougher than Kevlar. To check whether that reputation is deserved, he travels to the Blackledge Spider Lab at the University of Akron, a leading center for spider silk research.
Seven kinds of silk in one web 1:00
Before visiting the lab, Henry assumed a web was made of a single material, but a spider actually produces seven different types of silk. One kind anchors the web to a surface, another forms the stretchy spiral, a sticky silk catches prey, and yet another is used to wrap up trapped insects. All these threads are thinner than a human hair and look similar unless viewed under a microscope. The strongest of them is dragline silk, also called major ampullate silk, which forms the spokes and outer frame of the web and does most of the work stopping a flying insect.
Milking a spider for silk 2:00
To test dragline silk directly, the team knocks out a garden spider with carbon dioxide, tapes it down, and pulls silk from it by hand before attaching the thread to a custom machine built to reel silk from spiders. A single strand is then placed in a machine that slowly pulls on it while measuring stress, the force divided by the thread's tiny cross-sectional area, and strain, the amount of stretch relative to the original length. At first stress and strain rise together and the silk would spring back if released, but past a certain point the stretching becomes permanent, and eventually the thread snaps.
Comparing silk strength to steel 3:30
The silk sample breaks at about 600 megapascals of stress, meaning a spider silk rope with a cross section the size of a little finger could support roughly 60,000 newtons, the weight of a fully grown African elephant. The Darwin's bark spider, found in Madagascar and known for spinning webs up to 25 meters across rivers to catch flying insects, produces silk with an ultimate tensile strength of around 1,600 megapascals, more than twice as strong as the lab sample. Experimental ultra-high strength steel can reach nearly 3,000 megapascals, about three times stronger than typical dragline silk, but steel is also six times denser. Because of that density difference, a silk rope of the same mass and length ends up with six times the cross-sectional area, which means it can withstand roughly twice the force of ultra-high strength steel before snapping, a measure known as specific strength.
Why toughness matters more than strength 5:30
Strength alone is not enough, which Henry illustrates with the example of a rock climber falling rather than just hanging: stopping a fall quickly creates enormous force, while stretching the fall out over a greater distance absorbs the same energy more gradually and with less force. Spider silk works the same way when a bug hits a web, since a rigid structure like a brick wall would bounce the bug right off, while a stretchy web slows it down enough to stick and trap it. The lab's silk sample stretched to 70 percent of its length before breaking, and the total energy absorbed before breaking, shown as the area under the stress-strain graph, is called toughness.
Spider silk beats Kevlar on toughness 6:31
Kevlar, the material in bulletproof vests, has a toughness of up to 50 megajoules per cubic meter, and experimental ultra-high strength steel reaches about 170. The lab's spider silk sample measured about 205 megajoules per cubic meter, roughly four times Kevlar, while silk from the Darwin's bark spider can peak at 520 megajoules per cubic meter, about three times the strongest steel and ten times tougher than Kevlar. Kevlar is very strong but also stiff, so it fails before it can stretch far enough to absorb as much energy, which is why stretchy spider silk wins on toughness. As one researcher notes, spider silk is also produced through a kind of green chemistry, made at room temperature inside a living body from the same basic building blocks used to make hair and skin, unlike the high heat and caustic solvents used in most polymer manufacturing.
Nanocrystals and stretchy regions 7:30
The secret to spider silk's strength lies in how its building blocks, proteins called spidroins, are arranged inside the fiber. In some regions the spidroins line up closely in similar size and shape, forming rigid nanocrystals like stacked egg trays, while in other regions, called amorphous regions, they stay disordered and can move and change shape freely. Together they behave like tiny rigid blocks connected by elastic cords, so the amorphous regions let the silk stretch and absorb energy while the nanocrystals let it withstand a much larger pull, producing a material that is both stronger than steel by weight and tougher than Kevlar.
Centuries of failed silk harvesting 9:01
Despite its promise, spider silk has never been used commercially at scale, even though people have tried for centuries. In 1709 a Frenchman named Francois Xavier Bon collected hundreds of spider egg sacs and spun their silk into stockings, but he found it nearly impossible to gather enough material. Three centuries later, Simon Peers and Nicholas Godley led a years-long project in Madagascar in which workers hand-gathered more than a million golden orb weaver spiders to weave a single golden cape. Farming spiders directly does not work because spiders are cannibals and need enormous amounts of space, and even when silk is collected by hand, cooperative spiders yield only around 100 to 300 yards of silk each, which is why natural spider silk costs about 7 million dollars per kilogram, roughly 50 times the price of gold.
Early attempts to manufacture spider silk 10:00
Since farming spiders was impractical, scientists tried making the silk proteins artificially. By the late 1990s, researchers at DuPont inserted spider silk genes into E. coli bacteria and yeast, which multiplied and produced the proteins. In 2001 a German team tried implanting the genes into tobacco and potato plants, and around the same time a Canadian company called Nexia created genetically modified goats whose milk contained spider silk proteins. All of these methods successfully produced the proteins, appearing as a powder from bacteria and yeast, a gel-like liquid from plants, and a dissolved form in goat milk, but none of them resembled actual spider silk, showing that producing the raw protein is not the same as replicating how a spider actually spins it.
Spider Silk And Razor Design 25:30
The video pivots from spider silk cutting Derek's skin to a sponsored explanation of razor design. Facial hair resists cutting more than expected, and many razor blades are engineered thin enough that they bend under that resistance, a problem called blade flex.
Why Flex Causes Irritation 26:00
Most razors build in flex using springs, pivots, and flexible mounts meant to feel gentler, but this makes the cutting angle change constantly. An unsupported blade bends mid stroke, tugging hairs and micro cutting skin, which causes the irritation often assumed to be unavoidable.
Henson Shaving Solution 26:31
Henson Shaving, designed by aerospace machinists, uses a single precisely machined blade held with tight tolerances instead of letting it move, keeping the cutting angle consistent. Viewers are offered code Veritasium for 100 free blades with any razor purchase.
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