Watching out for vultures
Middle school science adventures
Silkís superpowers
Frogs and Toads
The Secret Lives of Grizzlies
Crocodile Hearts
Awake at Night
Brainy bees know two from three
Fighting fat with fat
Internet Generation
Flightless Birds
Chemistry and Materials
A New Basketball Gets Slick
Supergoo to the rescue
Earth from the inside out
Middle school science adventures
Seen on the Science Fair Scene
Small but WISE
Dinosaurs and Fossils
Dino Takeout for Mammals
A Big, Weird Dino
Dinosaur Eggs-citement
E Learning Jamaica
2014 GSAT Results for Jamaican Kids
Results of GSAT are in schools this week
E Learning in Jamaica WIN PRIZES and try our Fun Animated Games
Snowflakes and Avalanches
Ice Age Melting and Rising Seas
Drilling Deep for Fuel
Island Extinctions
The Wolf and the Cow
Food Web Woes
Finding the Past
Early Maya Writing
Preserving Ancient Warrior Paint
Meet your mysterious relative
Food and Nutrition
Eat Out, Eat Smart
The Essence of Celery
Yummy bugs
GSAT English Rules
Finding Subjects and Verbs
Who vs. That vs. Which
Problems with Prepositions
GSAT Exam Preparation Jamaica
Ministry of Education Announces 82 GSAT Scholarships for 2010
March 21-22, 2013: Over 43,000 students will take the GSAT Exam
Results of GSAT are in schools this week
GSAT Exams Jamaica Scholarships
Results of GSAT are in schools this week
GSAT Scholarship
GSAT Practice Papers | GSAT Mathematics | Maths
GSAT Mathematics
GSAT Practice Papers | GSAT Mathematics | Maths
It's a Math World for Animals
A Sweet Advance in Candy Packing
Human Body
Running with Sneaker Science
Taste Messenger
Gut Germs to the Rescue
St. Bernards
Blue Bear
Raise a Lifelong Reader by Reading Aloud
Expert report highlights the importance to parents of reading to children!
The Surprising Meaning and Benefits of Nursery Rhymes
The Particle Zoo
One ring around them all
Thinner Air, Less Splatter
Hungry bug seeks hot meal
Springing forward
Assembling the Tree of Life
Snapping Turtles
Space and Astronomy
Rover Makes Splash on Mars
An Earthlike Planet
Pluto's New Moons
Technology and Engineering
Squeezing Oil from Old Wells
Crime Lab
Sugar Power for Cell Phones
The Parts of Speech
What is a Noun
Countable and Uncountable Nouns
What is a Preposition?
Ready, unplug, drive
Robots on the Road, Again
Middle school science adventures
Either Martians or Mars has gas
Warmest Year on Record
The solar system's biggest junkyard
Add your Article

Supersonic Splash

Supersonic means faster than the speed of sound, which is about 760 miles per hour in air. Thatís a speed limit that can be broken ó by jets and bullets, for example, or by the space shuttle as it returns to Earth. Now, a scientist named Stephan Gekle has found that you can make air move faster than the speed of sound by doing a simple little trick: throw a rock in a pond. Gekle is a scientist at the University of Twente in the Netherlands who studies the physics of fluids. Physics is the study of forces and motion, and Geckle investigates how forces act on liquids, like water. In a recent study, he and his colleagues showed that after a rock drops into a body of water, a tiny jet of air shoots upward faster than the speed of sound. This isnít the first time Gekle has explored what happens when a rock sinks through water. In an earlier study, he and his team showed that as a rock falls into a flat surface of water, like a pond, it carves out a tiny tube of air. This tube connects the sinking rock to the air above the pond. The tube doesnít exist for very long, though ó almost immediately, the surrounding water pushes on the sides. This pressure is stronger in the middle than at the ends. As a result, the tube looks like an hourglass, where the middle gets smaller and smaller as the water forces the air out. Thereís not room in the hourglass for water and air, so as the water comes in the air escapes upward ó and fast. These tiny jets of air can blast faster than the speed of sound, Gekle found. To measure these air jets is trickier than it may seem. Gekle and his colleagues had to do more than stand at the edge of a pond with stopwatches. A careful science experiment requires a scientist to take multiple measurements of the exact same thing, to check and double-check the results. In this case, it would have been almost impossible for Gekle and his colleagues to throw a rock in a pond in the same way over and over again. Instead, the scientists created a lab experiment that acted like a rock falling through water: They dragged a circular disc down through water at the same speed, over and over again, and watched what happened. But there was another difficulty: Itís hard to see and measure air. To solve that problem, the scientists filled the air above the water with smoke and illuminated the smoke with a laser, which made the moving air easier to see. (To make the smoke, Gekle said, they used a smoke machine like the ones that provide the dramatic effects seen onstage at theaters.) Finally, because everything happens so fast when the rock moves through water, the scientists had to find a way to slow down time. As the disc moved through the water, the scientists took pictures with a camera that captured 15,000 frames every second. (Thatís faster than most movie cameras.) After the experiment, the researchers could slow down the movie and, aided by computer simulations, calculate the speed of air as it blew out of the hourglass-shaped tube. But thereís one aspect of supersonic air that Gekle and his team didnít observe. When a jet exceeds the speed of sound, the air around it produces a noise like thunder, called a sonic boom. So far, however, Gekle says the tiny air jets arenít making even a teeny, tiny boom ó but the researchers will keep listening. POWER WORDS (adapted from the Yahoo! Kids Dictionary) speed of sound About 760 miles per hour, through air at sea level. supersonic Faster than the speed of sound. physics The science of matter and energy and of interactions between the two, grouped in traditional fields such as acoustics, optics, mechanics, thermodynamics and electromagnetism, as well as in modern fields including atomic and nuclear physics, solid-state physics, particle physics and plasma physics. force The capacity to do work or cause physical change. pressure Force applied uniformly over a surface, measured as force per unit of area.

Supersonic Splash
Supersonic Splash

Designed and Powered by™