Why do rocks skip on water

McGhee likes ones that are about as heavy as tennis balls. Rectangular stones will veer off at an angle; triangular stones are the most stable on choppy water.

Irregular stones are McGhee's favorites. Stand at an angle to the water, your feet apart at shoulder width. Take a few warm-up throws with increasingly heavy stones. When you're ready, gather some stones and hold them in your non-throwing hand as a counterbalance. Then place one in the crook of your index finger and cock your wrist. Breathe in slowly through your nose, extending your arm high above your head.

When your lungs are full, whip your non-throwing arm across your body, then bring your throwing arm down and forward, rotating your shoulders degrees. Exhale forcefully as you throw, shifting your weight onto your lead foot. Snap your wrist at the end of its arc, releasing the stone parallel to the water with as much spin and speed as possible. If you are standing at the water's edge, your stone should first splash down no more than 15 feet away.

Follow through with your throwing arm's motion after the stone is released. Read a description of Roman shell skipping: www. A short essay on the HyperSoar, "Bringing Hypersonic Flight Down to Earth," on the Lawrence Livermore Web site gives details of the plane's potential and the technical challenges of building it: www.

The North American Stone Skipping Association's Web site has links to relevant sites and a collection of stone-skipping trivia: www. Register or Log In. The Magazine Shop. Login Register Stay Curious Subscribe. The Sciences.

Champion stone skipper Jerdone Coleman McGhee has been stopped going through customs with bags full of rocks and always carries a five-sided stone in his pocket. Newsletter Sign up for our email newsletter for the latest science news. Sign Up. Already a subscriber?

In order for your rock to skip, the water needs to be flat and calm. Try to find an area with rocky shore so you have a better chance of finding a stone you can skip. Look for a flat, smooth stone near the water. Try to find rocks that easily fit in your palm and weigh less than a tennis ball. The thinner the rocks are, the easier they will bounce across the surface of the water. Keep looking for rocks until you collect 10 or more so you don't have to look for new ones after each throw.

Experiment with different thicknesses and weights to see what kind of rock works best for you. Hold the stone between your thumb and middle finger. Clench the middle finger, ring finger, and pinkie on your dominant hand so you're making a partial fist. Set the rock on top of your middle finger and hold it firmly in place with thumb. Hook your index finger around the edge of the rock. Firmly wrap your index finger around the rock.

Your index finger adds spin to the rock once you throw it to help it skip across the water's surface. Part 2. Face the water at a slight angle with your arm low to the ground. Stand with your non-dominant arm facing the water so your body is at a degree angle. Keep your feet shoulder-width apart and your knees slightly bent. Extend your dominant arm at your side and hold the rock parallel to the ground.

Bring your arm and wrist behind you. Move your arm so it's behind your body, still keeping the rock parallel to the ground. Make sure your chest and shoulders are still facing the water. Bend your wrist backward so it's at a degree angle to your arm. Over time, you'll be able to skip rocks in one fluid motion. Throw your arm out in front of you and release the rock when it's in front of your body. Bend your knees as you move your dominant arm in front of your body.

Flick your wrist at the end of your throw and let go of the rock so it spins off your index finger and lands parallel to the water. The spinning will help the rock bounce off the water's surface so it skips multiple times. The flat bottom of the rock rides along the angle of the cavity, sending it airborne again so it can skip.

Instead, try to throw your arm quickly. If your rock doesn't skip the first time you try, take your time to readjust your form and try again. Practice makes perfect!

It should have a good horizontal spin so it can skip across the water. Try letting it spin off your index finger when throwing. Not Helpful 5 Helpful You can use anything as long as it has a similar shape and weight, but then it wouldn't be skipping rocks.

It'd be skipping clamshells. Not Helpful 6 Helpful Not Helpful 9 Helpful These stones do not have to perfectly round, but they need to be extremely smooth and have flat bottoms. He developed his own tossing style, which somehow defies science's paradigms regarding optimal skimming stone formulas. Steiner prefers to throw his stones fast at 30 degrees to an imaginary horizontal line, swiveling his shoulder back and bringing his arm like a whip. When the stone is thrown, it looks like it is going almost directly into the water, except by the time it hits the water, it's not actually going directly down and then comes out at about five degrees.

How do you skip a stone across an ocean, lake, river, or body of water? Here are a few tips that will help you become a better and more talented stone skipper.

The first thing you have to do is determine which side is going to be down. Flatter and slightly rounded are good; if it's cupped or jagged, put that up. It all depends on the water conditions, the stones you have, and distance versus skip count goals. For example, if you're aiming for multiple skips, you should attack the surface of the water with a steep rock release.

The brief time between release and the first skip - less than a second - is enough to change the landing orientation of the stone. Under high rotational and forward velocity, non-flat stones experience significant aerodynamic effects.

You might want to select rocks that spin aerodynamically against the gyroscopic twist, similar to the vertical propeller on a helicopter. One final word of advice: stone skimming can cause injuries. So, make sure to warm-up your muscles before trying your luck. The competition features five divisions: adults male and female competitors aged 16 years or more , juniors boys and girls aged years inclusive , children kids aged nine years and under , old tossers male and female competitors aged 60 or more and team maximum of four athletes of either gender and any age mix.

The stone must bounce on the surface of the water at least two times to be considered a valid skim. The length of the skim is judged until the stone sinks into the water. The longest skim in each division will be deemed the winner;. Competitors are not allowed a "run-up" when throwing. As a result, both feet must be on the platform when throwing;. A skim will be deemed invalid if: a the stone does not bounce at least two times; b the stone does not sink within the competition area;.

In case of a tie, the overall champion will be decided by the cumulative distance of a three-skim "toss-off. In the event of a tie in all other categories, rankings will be decided on a cumulative total of all three stones skimmed. Competitors do not need to bring their own "equipment" - skipping stones made of Easdale slate are available for all athletes. The duo battled each other competitively for over a decade and pushed the boundaries of stone skimming to the limits.

The film explores the physical and emotional challenges stone skippers face to stay at the top of their game while young guns make their way into the limelight. BBC Scotland also produced "Sink or Skim," an in-depth documentary on the sport, which reveals how stone skipping has played a considerable role in the development of Easdale Island.

Manasota Beach: a unique Floridian skimboarding spot.