The secret of stone skimming: choose flat round stones for jumps and get heavier for jumps
Anyone who has skimmed stones on a lake or by the sea knows that the flattest rounds are the best.
However, scientists now say that if you want to make a bigger impression, you should choose something bigger and curvier, as it will bounce higher and with greater speed.
Rock sliding has been around for thousands of years, but the new findings come from a model study of how solid objects slide over liquids.
Researchers from the University of Bristol and University College London found that a heavier object hurtles upwards more dramatically – because it dives deeper and has longer contact with water, creating a bigger wave.
Researchers from the University of Bristol and University College London found that a heavier object hurtles upwards more dramatically – because it dives deeper and has longer contact with water, creating a larger wave (stock image)
The best stones to skim
1. Smooth and flat stone – 5+ skims
2. Curved and potato-shaped stones – 2-3 skims
3. Lumpy and irregularly shaped stones – 1 skim
However, large rocks are unlikely to generate as many bounces.
Someone using a heavy rock will not be able to beat Kurt Steiner’s record for most jumps of a skimming rock, which the American set in 2013 with 88 jumps.
A heavier rock that is more curvy is more likely to slide without sinking, based on research from the University of Bristol and University College London.
dr Ryan Palmer, who led the research, said: “Rocks, which we would normally dismiss as too heavy when rock skimming, can still bounce off the water with a good throw, and in some cases leap with big and fast leaps – which are huge, surprising.” jumps generated.
“These are the stones I choose now when we take my daughters to the beach.
“They jump out of the water with such a mighty leap and like most fathers I will do anything to impress my children.”
dr Palmer performed the mathematical modeling to understand how ice on airplane wings bounces off surface water.
But the results are equally applicable to stone skimming and may even include some lessons in bouncing bombs like those used by the Dambusters.
Researchers confirmed that many heavy objects, such as large rocks used in rock skimming, would humiliatingly land with a pop and sink without a trace.
But heavy rocks with a curved bottom may not sink, as the evidence suggests, because they rotate more and push extra water away from them, creating more force to bounce them out of the water.
Heavier rocks fall with more force than lighter ones, falling deeper and longer, which also builds more power out of the water.
This means they are thrown higher, converting the horizontal force of the person flying over a rock into vertical force.
dr Palmer’s advice is, “Flat and circular for a lot of jumps, but heavier and curvier for fewer, bigger, more exciting jumps.”
Compared to a classic skimming stone, which is round and light, a stone eight times heavier can still be used for skimming if it has a fourfold curvature, the study found.
However, heavy rocks are thought to ricochet at a slightly wrong angle, making them sink after a ricochet or two rather than bouncing off the surface again.
Smooth stones are always better than jagged ones, according to the authors, and they should be longer than thick.
The research results were published in the journal Proceedings of the Royal Society A.
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The perfect way to skip a rock: throwing at an angle of 20 degrees increases the number of jumps when diving
A disk-shaped stone must be thrown at an angle of 20 degrees in order to achieve the maximum number of jumps over water
A disk-shaped stone must be thrown at an angle of 20 degrees in order to achieve the maximum number of jumps over water.
Inspired by the English scientist Barnes Wallis, who invented the bouncing bomb, researchers have described the intricate physics behind the water-bouncing behavior of rocks, toys and even cannonballs.
As early as the 18th century, gunners ricocheted cannonballs as a military tactic and eliminated firing angle as a variable in sinking enemy ships.
Professor Tadd Truscott of Brigham Young University in Utah and his colleagues said: “Barnes Wallis recaptured the variable reducing military advantage during World War II with his bouncing bomb.
“The weapon was designed to breach German levees and leapt above the water surface to avoid underwater torpedo nets.”
https://www.dailymail.co.uk/sciencetech/article-11596689/Stone-new-science-skimming-heavy-stuff.html?ns_mchannel=rss&ns_campaign=1490&ito=1490 The secret of stone skimming: choose flat round stones for jumps and get heavier for jumps