Agriculture
Protecting Cows—and People—from a Deadly Disease
Where Have All the Bees Gone?
Chicken Eggs as Drug Factories
Amphibians
Bullfrogs
Frogs and Toads
Salamanders and Newts
Animals
Tool Use Comes Naturally to Crows
New Elephant-Shrew
A Fallout Feast for Crabs
Behavior
Meet your mysterious relative
Mosquito duets
Storing Memories before Bedtime
Birds
Cassowaries
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Birds We Eat
Chemistry and Materials
Diamond Glow
Sticky Silky Feet
Gooey Secrets of Mussel Power
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A Classroom of the Mind
Programming with Alice
Hitting the redo button on evolution
Dinosaurs and Fossils
A Big, Weird Dino
Ferocious Growth Spurts
Dinosaur Dig
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2014 GSAT Results for Jamaican Kids
Results of GSAT are in schools this week
Earth
The Pacific Ocean's Bald Spot
Meteorites may have sparked life on Earth
Wave of Destruction
Environment
The Wolf and the Cow
Blooming Jellies
Where rivers run uphill
Finding the Past
Unearthing Ancient Astronomy
Stonehenge Settlement
Meet your mysterious relative
Fish
Halibut
Puffer Fish
Seahorses
Food and Nutrition
Sponges' secret weapon
Packing Fat
A Pepper Part that Burns Fat
GSAT English Rules
Capitalization Rules
Finding Subjects and Verbs
Who vs. Whom
GSAT Exam Preparation Jamaica
GSAT Practice Papers | GSAT Mathematics | Maths
10 Common Mistakes When Preparing for the GSAT Math Test
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GSAT Mathematics
Losing with Heads or Tails
Math and our number sense: PassGSAT.com
It's a Math World for Animals
Human Body
Music in the Brain
A Long Trek to Asia
Teen Brains, Under Construction
Invertebrates
Termites
Millipedes
Cockroaches
Mammals
Wolves
Chinchillas
Oxen
Parents
Choosing a Preschool: What to Consider
The Surprising Meaning and Benefits of Nursery Rhymes
Expert report highlights the importance to parents of reading to children!
Physics
The Pressure of Scuba Diving
Hold on to your stars, ladies and gentlemen
Spin, Splat, and Scramble
Plants
A Change in Leaf Color
Fast-flying fungal spores
Pumping Up Poison Ivy
Reptiles
Black Mamba
Komodo Dragons
Tortoises
Space and Astronomy
Asteroid Moons
An Earthlike Planet
Mercury's magnetic twisters
Technology and Engineering
Weaving with Light
Riding Sunlight
Squeezing Oil from Old Wells
The Parts of Speech
What is a Verb?
Problems with Prepositions
What is a Preposition?
Transportation
Middle school science adventures
Ready, unplug, drive
Tinkering With the Basic Bike
Weather
A Change in Climate
In Antarctica watch the heat (and your step)
Recipe for a Hurricane
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Deep History

The Grand Canyon is one of nature's most majestic and impressive places. The gorge is enormous, measuring 277 miles (446 kilometers) long and up to a mile (1.6 km) deep in some places. The Colorado River runs through the middle of it. But how old is it? Now, scientists have collected new clues about the canyon's ageThe canyon's walls are full of caves that contain lumps of minerals called mammillaries. These mound-shaped lumps usually form just below the surface of pools that are full of minerals. Water levels in such pools can drop when, for example, a change in climate occurs or the Earth's crust shifts. The mammillaries remain, even when the water level drops. Scientists can analyze concentrations of metals inside the mounds to figure out when their pools went dry. Carol Hill, a geologist at the University of New Mexico in Albuquerque, and colleagues studied mammillary formations in nine caves near the Grand Canyon. Most of these caves lie within a few miles of the Colorado River, which carved the rocky gorge. All the sampled mounds were within three-quarters of a mile (1.2 km) above the river's current level. Analyses of the mounds in the western region of the Grand Canyon suggest that 17 million years ago the level of groundwater in the area was about 3,800 feet (1,160 meters) higher than it is today. By 7.6 million years ago, the water had dropped to 3,050 feet above the river's current level. About 2 million years ago, the water was only 390 feet (120 m) higher than it is today. Over that time, water levels dropped as the river carved deeper into the canyon's floor. In the eastern region of the Grand Canyon, analyses suggest that the river's carving action started much later but took place far more quickly. In that area, the groundwater level (and probably the river level) dropped almost as far as it did on the western side, 3,000 feet (920 m), but in only one-fifth the time—just the past 3.7 million years. Together, these data suggest that the Colorado River began carving the Grand Canyon at its western end. Later, the process appears to have continued upstream.—Emily Sohn

Deep History
Deep History








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