Agriculture
Keeping Bugs Away from Food
Getting the dirt on carbon
Cleaning Up Fish Farms
Amphibians
Toads
Bullfrogs
Salamanders and Newts
Animals
New Monkey Business
Color-Changing Bugs
Sleepless at Sea
Behavior
Brain cells take a break
Meet your mysterious relative
How Much Babies Know
Birds
Hawks
Blue Jays
Penguins
Chemistry and Materials
Sticking Around with Gecko Tape
Smelly Traps for Lampreys
Sticky Silky Feet
Computers
Music of the Future
Secrets of an Ancient Computer
The Earth-bound asteroid scientists saw coming
Dinosaurs and Fossils
Dino Bite Leaves a Tooth
A Rainforest Trapped in Amber
Dino-bite!
E Learning Jamaica
Results of GSAT are in schools this week
E Learning in Jamaica WIN PRIZES and try our Fun Animated Games
2014 GSAT Results for Jamaican Kids
Earth
Coral Islands Survive a Tsunami
What is groundwater
Weird, new ant
Environment
A Change in Leaf Color
Power of the Wind
Indoor ozone stopper
Finding the Past
Fakes in the museum
The Puzzle of Ancient Mariners
Words of the Distant Past
Fish
Perches
Hammerhead Sharks
Codfish
Food and Nutrition
Recipe for Health
Building a Food Pyramid
Sponges' secret weapon
GSAT English Rules
Finding Subjects and Verbs
Pronouns
Adjectives and Adverbs
GSAT Exam Preparation Jamaica
March 21-22, 2013: Over 43,000 students will take the GSAT Exam
GSAT stars reap scholarship glory
Scotiabank Jamaica Foundation Grade Six Achievement Test (GSAT) Scholarships
GSAT Exams Jamaica Scholarships
Results of GSAT are in schools this week
Access denied - Disabled boy aces GSAT
GSAT Exam Preparation
GSAT Mathematics
Losing with Heads or Tails
GSAT Practice Papers | GSAT Mathematics | Maths
Play for Science
Human Body
A New Touch
From Stem Cell to Any Cell
Workouts: Does Stretching Help?
Invertebrates
Crustaceans
Ticks
Tarantula
Mammals
Pugs
Rodents
Golden Retrievers
Parents
What Not to Say to Emerging Readers
Choosing a Preschool: What to Consider
Raise a Lifelong Reader by Reading Aloud
Physics
Echoes of a Stretched Egg
One ring around them all
The Particle Zoo
Plants
Hungry bug seeks hot meal
Assembling the Tree of Life
Cactus Goo for Clean Water
Reptiles
Caimans
Turtles
Komodo Dragons
Space and Astronomy
A Dusty Birthplace
Burst Busters
Cool as a Jupiter
Technology and Engineering
Roll-Up Computer Monitors to Go
Searching for Alien Life
Space Umbrellas to Shield Earth
The Parts of Speech
Adjectives and Adverbs
What is a Verb?
What is a Preposition?
Transportation
Revving Up Green Machines
Where rivers run uphill
Are Propellers Fin-ished?
Weather
A Change in Climate
Antarctica warms, which threatens penguins
Arctic Melt
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™