Non-newtonian fluids are the best. I mean who doesn’t love something that is a solid under high strain rates and a liquid under low strain rates. Oobleck is one of these fluids and it makes for a pretty fun slimy toy to play with. You can slowly dip your hand into it like a liquid, but if you try to clench your fist very fast, it will firm up, like a solid. So naturally, the next experiment you would want to try is filling balloons with it and then shooting objects at them and recording it in high speed right? Well that’s exactly what backyard scientist did, and it is an incredibly messy, yet satisfying video filmed in high speed, check it out.
First, they see how the oobleck reacts to a chainsaw, will it respond like a solid or a liquid? When you take a chainsaw to a balloon filled with water, the water simply falls straight to the ground, unaffected by the rotating chain. The non-newtonian fluid however will react like a solid under the force of the chain shooting forward and then fall to the ground like a liquid.
By far the best part of the video comes when they decide to shoot a golf ball at over 300 feet per second at the balloon, and it is quite a sight to see. Upon impact, the fluid reacts like a solid and sprays in every direction, quickly returning to a liquid state and creating a big mess in their backyard. If you want to make yourself some non-newtonian fluid and play with it at home, all it takes is some water and cornstarch!
[Image Source: Backyard Scientist]
Physics is awesome, and sometimes even though you know the math behind how something will react, you never expect it to look as awesome as it does. Seeing a liquid turn into a solid during an explosion, then turning back into a liquid as it falls to the ground is pretty awesome no matter who you are.