4 ms·
They always use shear-thickening fluids because they're so counterintuitive, but shear-thinning fluids are a fun example of a mixed blessing — the same property
by pdpi 4y ago
They always use shear-thickening fluids because they're so counterintuitive, but shear-thinning fluids are a fun example of a mixed blessing — the same property that keeps paint from dripping off a brush/roller until you apply it is also what makes it so hard to pour the right amount of ketchup.
- raverbashing 4y agoYeah, true. The ketchup one I don't think it's "on purpose" (hence why it's annoying)
- shagie 4y agoThere was a chemistry professor trying to get an idea of some testing of this property and set up an experiment for dropping a weight through ketchup and timing it followed by another one shortly after. The second one will fall through the ketchup faster. How do you measure this? How much ketchup do you need? The initial approach was a large cylinder holding the ketchup with the bottom clear - and then a mirror set up under that. It also was initially done with a human with a stop watch and they needed enough ketchup so that the difference would be noticeable and within the error of human reactions. It takes a lot of ketchup to fill up a 2 meter by 20 cm cylinder. Can't make it too narrow because the edges change it. The grad students bought all the ketchup at the local big grocery store and raised a few eyebrows at the checkout. After proving that it worked they were able to make a clear polymer fluid that had the same properties (though was more expensive than ketchup) so that they were able to see it from the side and provide better timings... and not have to worry about spoilage... still, the grad students with 16 gallons of ketchup was something to remember. They did a bratwurst cookout with the unused leftovers.