Agriculture
Where Have All the Bees Gone?
Protecting Cowsóand Peopleófrom a Deadly Disease
Making the most of a meal
Amphibians
Newts
Tree Frogs
Bullfrogs
Animals
Monkey Math
A Butterfly's New Green Glow
Bee Heat Cooks Invaders
Behavior
The chemistry of sleeplessness
Pollution at the ends of the Earth
Meet your mysterious relative
Birds
Doves
Tropical Birds
Woodpecker
Chemistry and Materials
The Taste of Bubbles
The newest superheavy in town
Diamond Glow
Computers
It's a Small E-mail World After All
Two monkeys see a more colorful world
Music of the Future
Dinosaurs and Fossils
The bug that may have killed a dinosaur
Message in a dinosaur's teeth
Meet your mysterious relative
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
Earth
Drilling Deep for Fuel
Slower Growth, Greater Warmth
Petrified Lightning
Environment
Eating Up Foul Sewage Smells
Ready, unplug, drive
Watching for Wildfires in Yellowstone
Finding the Past
Words of the Distant Past
Traces of Ancient Campfires
Big Woman of the Distant Past
Fish
Flashlight Fishes
Puffer Fish
Great White Shark
Food and Nutrition
Packing Fat
Strong Bones for Life
Sponges' secret weapon
GSAT English Rules
Capitalization Rules
Finding Subjects and Verbs
Who vs. That vs. Which
GSAT Exam Preparation Jamaica
Ministry of Education Announces 82 GSAT Scholarships for 2010
2014 GSAT Results for Jamaican Kids
GSAT Practice Papers | GSAT Mathematics | Maths
GSAT Exams Jamaica Scholarships
Access denied - Disabled boy aces GSAT
Results of GSAT are in schools this week
GSAT stars reap scholarship glory
GSAT Mathematics
How to Slice a Cake Fairly
Math Naturals
A Sweet Advance in Candy Packing
Human Body
Electricity's Spark of Life
Taking the sting out of scorpion venom
From Stem Cell to Any Cell
Invertebrates
Walking Sticks
Daddy Long Legs
Octopuses
Mammals
Tigers
Marmots
African Elephants
Parents
Choosing a Preschool: What to Consider
How children learn
Expert report highlights the importance to parents of reading to children!
Physics
The Pressure of Scuba Diving
Extra Strings for New Sounds
IceCube Science
Plants
Surprise Visitor
Flower family knows its roots
Nature's Alphabet
Reptiles
Rattlesnakes
Alligators
Black Mamba
Space and Astronomy
A Planet's Slim-Fast Plan
Planning for Mars
Sun Flips Out to Flip-Flop
Technology and Engineering
Bionic Bacteria
Young Scientists Take Flight
Spinach Power for Solar Cells
The Parts of Speech
What is a Noun
Adjectives and Adverbs
Countable and Uncountable Nouns
Transportation
Robots on the Road, Again
Seen on the Science Fair Scene
Morphing a Wing to Save Fuel
Weather
Science loses out when ice caps melt
Either Martians or Mars has gas
In Antarctica watch the heat (and your step)
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 HBJamaica.com™