You cannot download interactives. Ocean currents are the continuous, predictable, directional movement of seawater driven by gravity, wind Coriolis Effect , and water density. Ocean water moves in two directions: horizontally and vertically. Horizontal movements are referred to as currents, while vertical changes are called upwellings or downwellings. Explore how ocean currents are interconnected with other systems with these resources.
A rip current is a strong flow of water running from a beach back to the open ocean, sea, or lake. A current is the steady, predictable movement of a fluid within a larger body of that fluid.
Fluids are materials capable of flowing and easily changing shape. A beach is a narrow, gently sloping strip of land that lies along the edge of an ocean or a lake. Join our community of educators and receive the latest information on National Geographic's resources for you and your students. Skip to content. Once the receding wave makes its way through the sandbar opening and meets up with water at its own level, its pressure immediately drops.
Overall, the water flow pattern has a mushroom shape. Depending on its severity, you may be able to see a rip current from the beach. Strong rip currents disrupt incoming waves and stir up sand from the ocean floor. When you're at the beach, keep an eye out for narrow, muddy streaks in the ocean where there aren't any waves breaking. If you get caught up in a rip current, it's crucial that you keep your wits about you.
Your first instinct may be to swim against the current, back to shallow waters. In most cases, even if you're a strong swimmer, this will only wear you out. The current is too strong to fight head-on. Instead, swim sideways , parallel to the beach see illustration below. This will get you out of the narrow outward current, so you can swim back in with the waves helping you along.
If it's too hard to swim sideways while you're being dragged through the water, just wait until the current carries you past the sandbar. The water will be much calmer there, and you can get clear of the rip current before heading back in.
People drown when they thrash about in the water or expend all of their energy swimming. To survive a rip current , or any crisis in the water, you have to keep calm, and you have to conserve your energy. If you don't think you can swim all the way back to the beach, get past the rip current and tread water. Call for help, signal to people on the beach and, if all else fails, wait for the waves to carry you in.
If you're on the beach and see somebody else caught in a rip current, call for help from a lifeguard or the police. Don't immediately dive in and swim out to the person. It's too risky to swim out there yourself unless you have a raft, boogie board or life preserver with you. The most effective way to fight rip currents is to follow basic swimming safety rules: Never go in the ocean alone , and if you aren't a strong swimmer, stick to shallow waters although even shallow waters can be dangerous.
Ideally, you should only swim in areas where there is a lifeguard or strong swimmer on the beach who can keep an eye on you. If you plan to swim in the ocean anytime soon, it's a good idea to learn everything you can about rip currents. However, they have been known to flow as fast as 8 feet per second about 5 miles per hour —faster than an Olympic swimmer can sprint!
They can sweep even the strongest swimmer out to sea. Rip current speed is influenced by the size of the waves, but sometimes waves only two feet high can produce hazardous rips. Perhaps surprisingly, rip currents are strongest at low tide. The shape of the ocean bottom sometimes changes during storms or when waves are particularly big.
The ocean floor may suddenly have an ideal shape for creating unpredictable rip currents where there were none before. Rip currents are much more dangerous, because they flow on the surface of the water, can be very strong, and can extend some distance from the shore. Home Education Currents Rip Currents. Rip Currents Currents Tutorial. Age of Exploration What is a "knot"? References Roadmap to Resources Subject Review.
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