Is Black Widow Silk Stronger Than Steel?

[MoonGlow]

2:34 "Now I have one single strand of black widow silk"
You also have a black widow running free in your house...

[yat]

Hi James! As others have mentioned, you did your first ultimate tensile strength calculation wrong -- you need to take into account the angles of the two threads. I measured a screenshot taken right before failure and found the thread on the left was 30deg. from horizontal and the thread on the right was 24deg. from horizontal.

I'm a physics/math teacher and have a degree in mechanical engineering so I had some fun re-doing the calculations. The actual ultimate tensile strength is 1.37GPa -- better than you thought! Let me know if you'd like a link to the PDF. (I don't think I can post a dropbox link here.) :)

IMO the biggest sources of error is your diameter measurement -- it doesn't look like you had very high resolution in the microscope capture, and there's always a possibility that the thread had a weaker/thinner spot somewhere you didn't look.

Also note that for the pulling-up-from-jar method, any tiny spikes in tension force due to slight shakiness of your hand will not be picked up by the reading on the scale, due to the inertia of the heavy glass jar and scale bed. If you want to try the pulling-up-from-jar method again for a more accurate result, I would recommend using the duct tape to attach the silk to a stretchy material like a strand of spandex from old underwear/socks, to absorb shocks and allow you to turn translational motion with your hand into a slow, steady force increase.

[amosbackstrom]

The craziest thing is, they didn't develop a unique new polymer to achieve these incredible strengths. The use amino acids, just like most other biological structures. They're just tangled up and cemented together in an incredibly complex way, so nearly every available bonding site is fully utilized.

[Salinated]

As someone from Texas, Black widows are actually sorta chill. Not so chill I'd invite them to my house for coffee, but they aren't bothering me either

[enox]

Sets world’s brightest flashlight down, without turning it off. I was half expecting the desk to burst into flames

[randyj]

My uncle raised Black Widows in our shed in the 80s. Sold webs and whole spiders. Been bit twice. The Bite Feels like a blow torch but the Stomach Cramps later are the worst!

[Jay]

There is a problem in your calculation.
You did not take into acount the angle of the silk.
When you are lifting heavy equipment, if you use 1 ton slings, and you have them at a 45° angle, you can only lift 500kg with them.

[okayolamaxmin]

The Action Lab is one of my favourite channels... in fact measured over time - The Number One - due to too many consistent variables to mention... down-to-earth enquiry, passion, scientific methodology, good humour...
Cheers & thank goodness for Action Lab

[ClintsReptiles]

Your methods are so brilliant! Thank you for another fascinating and educational video.

[penobscot]

Bros videos keep getting more dangerous

[erykmozejko]

Just did a quick repair on a theodolite cross hairs last week. Black widow silk is highly recommended for these. Good fine consistent diameter with a good strength in order to be fitted accurately and taut enough.

[SerkanKabak]

That ‘kickback’ behavior at 0:08 is characteristic of black widows, I’ve witness them do it towards objects like sticks when pressed against their abdomens.

[sachiperez]

i love it when you explain the methods you use, measuring pixels and all!

[AddyAdderson]

At 2:59, I can't hear a thing you say, because my mind is ablaze with the question, "now where the hell did that spider go?"

[NinjaNezumi]

You did the test a bit wrong - you're only supposed to calculate the tensile strength from a certain amount of deformation usually labeled at the failure point. When it deforms too much you should stop counting. I think the deformation was certainly past the critical failure point at around 8 - meaning it would've snapped after being left alone for a few more minutes. The failure point was 6 or 7.

[leeborocz-johnson]

One time at summer camp in Tennessee in 2006, there was a black widow nested in the ceiling joists of the latrine of my troop's campsite. I noticed it the 2nd or 3rd day of camp, and just looked up at it, hanging out there, every time I went to have a seat. I knew about black widows but gor some reason I just thought nothing of it and didn't say anything to anyone. No one else noticed it until the last day of camp, when the Scoutmasters called in the camp ranger and the established a friggin' perimeter and no one could go to the bathroom for an hour.

[Csj]

I've watched you for years but this video is one of my favorites.

[jkddaddy]

Ultimate tensile strength is a sexy engineering and intuitive measure but another key property that goes hand in hand is the ductility. In other words how much stretch does the strand have before failing?
This would be super interesting to compare to the other materials you reference.
You’ll notice that in most cases higher strength materials are also a lot stiffer or less ductile.

[skylerthacreator]

0:52 scientists have finally begun to realize they exist

[GIGACHAD-jjwl]

I love the fact that at the start he says "it's the deadlist spider" then proceed to touch it