Agriculture
Where Have All the Bees Gone?
Watching out for vultures
Protecting Cows—and People—from a Deadly Disease
Amphibians
Poison Dart Frogs
Salamanders
Bullfrogs
Animals
Ultrasonic Frogs Raise the Pitch
Cannibal Crickets
Ants on Stilts
Behavior
How Much Babies Know
A Light Delay
Between a rock and a wet place
Birds
Ibises
Songbirds
Blue Jays
Chemistry and Materials
Big Machine Reveals Small Worlds
Picture the Smell
Sugary Survival Skill
Computers
Look into My Eyes
Computers with Attitude
A Classroom of the Mind
Dinosaurs and Fossils
Dino-Dining Dinosaurs
Ferocious Growth Spurts
Winged Insects May Go Way Back
E Learning Jamaica
2014 GSAT Results for Jamaican Kids
E Learning in Jamaica WIN PRIZES and try our Fun Animated Games
Results of GSAT are in schools this week
Earth
Slip Slidin' Away—Under the Sea
Springing forward
The Pacific Ocean's Bald Spot
Environment
Inspired by Nature
Missing Tigers in India
A Change in Leaf Color
Finding the Past
Chicken of the Sea
Digging Up Stone Age Art
A Volcano's Deadly Ash
Fish
Mako Sharks
Bass
Trout
Food and Nutrition
Strong Bones for Life
A Pepper Part that Burns Fat
Chew for Health
GSAT English Rules
Finding Subjects and Verbs
Who vs. That vs. Which
Order of Adjectives
GSAT Exam Preparation Jamaica
2014 GSAT Results for Jamaican Kids
GSAT Scholarship
GSAT Exam Preparation
GSAT Exams Jamaica Scholarships
GSAT Practice Papers | GSAT Mathematics | Maths
Access denied - Disabled boy aces GSAT
GSAT stars reap scholarship glory
GSAT Mathematics
A Sweet Advance in Candy Packing
42,000 students will sit for the GSAT Exam in two weeks
Prime Time for Cicadas
Human Body
Taste Messenger
Flu Patrol
From Stem Cell to Any Cell
Invertebrates
Flies
Camel Spiders
Sea Anemones
Mammals
Bobcats
Giant Panda
Dalmatians
Parents
Raise a Lifelong Reader by Reading Aloud
How children learn
What Not to Say to Emerging Readers
Physics
Strange Universe: The Stuff of Darkness
The Particle Zoo
One ring around them all
Plants
White fuzzy mold not as friendly as it looks
Tracking the Sun Improves Plant Pollen
Farms sprout in cities
Reptiles
Crocodiles
Snakes
Sea Turtles
Space and Astronomy
Roving the Red Planet
Planets on the Edge
A Planet's Slim-Fast Plan
Technology and Engineering
Algae Motors
Beyond Bar Codes
Weaving with Light
The Parts of Speech
What is a Noun
Adjectives and Adverbs
Countable and Uncountable Nouns
Transportation
Flying the Hyper Skies
Revving Up Green Machines
How to Fly Like a Bat
Weather
Watering the Air
A Change in Climate
The solar system's biggest junkyard
Add your Article

Fog Buster

If you've worn goggles for skiing or swimming, you've probably been annoyed by the way they can cloud up. Or, if you've used a Game Boy, you might have noticed how screen glare can wipe out crucial details as you play a tricky videogame. The problems of fogging and glare don't seem to have much in common. But materials scientists are finding that they can solve both problems at the same time. The secret is to put a coating with the right combination of chemicals and texture on the surface of the glass or plastic. Clearing up fog Fog forms on a mirror or window when water vapor in warm, moist air condenses to create tiny water droplets on the smooth, cool surface. Instead of letting light through, the droplets tend to scatter light in different directions. This makes it hard to see through the glass. What you do see looks blurry. To deal with this problem, Michael Rubner considered the way droplets form on surfaces with different textures. He's a materials scientist at the Massachusetts Institute of Technology. Like many researchers who work on materials, Rubner was inspired by nature. In this case, he looked at the leaf of the Japanese lotus flower, which causes water to bead into rounded droplets (see "Inspired by Nature" and "Butterfly Wings and Waterproof Coats"). The surface of a lotus leaf is waxy and filled with tiny holes, so it looks a bit like a sponge. The waxy substances on the leaf's surface repel water. At the same time, air trapped in the holes keeps water from sticking. To create a coating that prevents fogging, Rubner's idea was to replace the waxy substances with chemicals that attract water. Making a nanosponge To make the new anti-fog coating, Rubner and his coworkers use a material called silica. Silica consists of the elements silicon and oxygen. It's found in most kinds of rock, and it's the main chemical compound in sand and glass. Silica also tends to attract water molecules. The researchers work with tiny silica particles, each one just a few nanometers wide. A nanometer is one-billionth of a meter. In comparison, a human hair is about 80,000 nanometers wide. A nanometer-sized particle is much smaller than a living cell and can be seen only by the most powerful microscopes available today. The scientists form the coating layer by layer by dipping a glass surface into a mixture of water and silica (or glass) nanoparticles, then into a mixture containing a type of plastic, or polymer. The plastic substance acts like glue, holding the glass particles together. The final coating has as many as 20 thin, alternating layers of polymer and glass particles. The result is a coating with lots of air pockets—like a thin "nanosponge" made of glass, Rubner says. Yet, the particles and holes are so small that the coated glass still looks and feels smooth. When exposed to warm, moist air, the coated glass surface attracts water. Instead of beading into rounded droplets, however, the water gets sucked into the holes all over the surface. This spreads out the water, and the resulting water film doesn't scatter light in the same way that droplets do. You can still see through the glass. A glaring improvement The new coating also changes the way in which light interacts with glass. Light moves very quickly, but it moves more slowly through glass than through air. Because of this mismatch, when light hits glass, some of it reflects off the surface, leading to glare. Because of the air pockets within the spongy coating, the coated glass surface acts like a mixture of glass and air when light hits it. This combination means that almost all of the light goes through the glass. Very little light is reflected. There's no more glare. In addition to improving Game Boy screens, this type of coating could lead to better windows for greenhouses, Rubner says. In a greenhouse with coated glass that reduces glare and resists fogging, more light gets in, so plants have more light for growth. Stronger coatings A coating isn't practical if it scratches or rubs off easily, however. To make the materials more durable, Rubner and his team heat the coatings to a high temperature, about 500 degrees C. Heating works fine for glass, but heated plastics will melt or even burn up. So, at this point, only materials that can stand high temperatures can be coated with the new anti-fog and anti-glare film. In Australia, Paul Meredith and Michael Harvey of the University of Queensland have taken a similar approach. They also use porous silica—a thin layer of glass filled with tiny holes—as a coating. But their procedure for creating the coating is somewhat different. Meredith and Harvey have even solved the problem that Rubner and his group are still working on. Their porous silica coatings are durable on both plastic and glass. The two researchers have formed a company, called XeroCoat, to make such coatings for solar cells. In 2 to 5 years, you might be shopping for improved eyeglasses or ski goggles or riding around in a car with a windshield that resists fogging and reduces glare. It'd be a new window on the world, thanks to materials research.

Fog Buster
Fog Buster








Designed and Powered by HBJamaica.com™