Joseph Njihia

Magic Angle Of Skipping Rocks

The world record holder at skipping rocks, kinda, sucks at it. So do you and so does everybody not to come screaming in with a hot take about a relaxing outdoor Pastime with zero Stakes, but it`s true because while the world record is 88 skips in a row, researchers predict we should be able to do hundreds, but we can`t and in our quest to understand why researchers have uncovered some real-world applications including bringing astronauts safely back from space. I`m pretty stoked if I can get three skips, so 88 seems unfathomable, but from what we know of the physics behind Rockskipping it`s possible the throw itself involves two things speed and angles. First, imagine the throw, the stone has to be traveling quickly in order to have enough momentum to keep going after making contact with the water and it's not just traveling really fast in a straight line, the stone is angled slightly in order to collide with the water on top of that, the stone needs to be rotating which you accomplish by holding the stone with your forefinger on the Leading Edge as you throw.This rotation is part of the key to success because it gives the stone stability as it flies through the air, as the stone collides with the water there is a couple of forces acting on it. The water pushes up on the moving Stone as it makes an impact causing the stone to skip the Collision and also causing the water itself to move creating ripples,these ripples will add some drag and slow its momentum. You'll notice that as the stone begins to lose momentum it starts skipping more frequently and the height of its skips decreases until all of a sudden the fun is over. Fun fact professional Skippers call these frequent Skips a Pity patch so if the goal is to maximize your skips and get somewhere in the same ballpark as the world record, you have to do a few things to overcome the forces acting on the stone. You need to pick a flat lightweight Stone so the upward force of the water is greater than the weight of the stone, otherwise, it will just sink as soon as it hits. In a 2004 nature paper about skipping stones, the authors identify the magic of the angle of attack when throwing your stone. They found that using a 20-degree angle in relation to the surface of the water maximizes the number of Skips and minimizes the amount of energy lost keeping the stone skipping longer even with all the forces acting against the stone models. Like this say we could create even more skips but why is this so hard to put into practice? First it's really hard to throw fast with spin while at the same time being very accurate about hitting the magic angle of attack, at that point, you're talking major league baseball pitcher levels of power and precision, and most pitchers don't Moonlight as Stone Skippers but even if you could achieve that combination, there are a lot of other factors working against you. For one thing, Mother Nature didn't make all Stones perfectly flat and round discs, and researchers say that the best-skipping Stones aren't stones at all. If you could you'd use something a bit squishy that deforms as it connects with the water like a rubber ball but that's littering, so don't do that. Also, most models simplify the real-world environment neglecting things like wind and waves all of which act against the stone, so while way more than 88 skips could be possible in reality there are too many factors that are out of our control to make that happen without the help of a controlled environment. German and maybe a robot but in the pursuit of trying to understand skipping Stonephysics researchers have found some real-world applications for example skipping technique was applied to the Orion capsule that landed in December 2022. This was the first successful uncrewed mission of NASA's Artemis. The program which will one day use Orion to take humans farther than they've ever traveled. When Orion was headed back to Earth it skipped off of our atmosphere before re-entry it's not quite the same as a stone skipping on the surface of the water but it did dip in and out of the Earth's atmosphere as it changed its trajectory to intersect with Earth. The moves accomplished a number of things. It helped the spacecraft land more accurately so the crew could be recovered in a more precise location, it also helped slow the speed of the spacecraft in the same way the water does when a stone skips on it while also reducing the amount of heat being generated by the high-speed entrance. While Orion was the first to successfully skip across Earth'satmosphere, the Apollo missions also had the capability though not the confidence to use this strategy. They did however inspire the application of this technique to the Orion mission in order to make the journey safer for the crewaboard. Spacecraft re-entry is only one thing we've been able to learn about thanks to the physics behind a simple game, but sometimes it's just fun to learn a little more about an afternoon by the lake too. Skipping Stones is a lot harder than it seems after all If energy momentum conservation is as reliable as the fancy physicists say it is you should be able to throw a little Stone as far as the eye can see. To learn more about energy-momentum conservation you can go to brilliant.org scishow.