RP294 Metamaterial

 RP294 Metamaterial

It's not only fantasy authors who are interested in invisibility. Real scientists are fascinated by the idea, too. And lately, instead of being dismissed as impossible, some researchers are saying, “Invisibility cloaks? Hmmm, maybe...”

The key is metamaterial. Metamaterials are man-made structures that bend light in very different ways than natural structures or materials do. When a beam of light hits a natural material—water, for example—The angle of the light changes somewhat, but the overall direction remains the same. When light hits some metamaterials, however, it actually changes direction and points backward. This bounce-back effect can trick our eyes into thinking we don't see anything. Because of the way they affect light, metamaterials are also called backward wave media, left-handed media, and other names.

Researchers at the University of California, San Diego, first showed that they could manipulate light this way in 2000. They created a new kind of material that had properties never seen in nature. One of them was this ability to reverse light. Since then, researchers have been working on repeating those results with different, more flexible materials and for different types of light. In July, 2010, Elena Semouchkina of the University of Michigan presented an invisibility device made of a type of modified glass. Semouchkina's device bends light around an object, hiding it.

In November of 2010 there was another breakthrough. Researchers at Saint Andrews University made a flexible metamaterial that can bend some light wavelengths, including the wavelength we see as the color red. Though their samples are only millimeters long, their creators are confident that they can make bigger ones.

The words “hiding,” “disguise” and “out of sight” may soon have a whole new meaning.

RP286 Pros and Cons of Nuclear Power

 RP286 Pros and Cons of Nuclear Power

Nuclear energy inspires passionate debate. As the world struggles to solve its energy problems, some believe nuclear power is our savior. Dramatic accidents and near misses, however, have convinced its opponents that nuclear energy must be discontinued.

Nuclear accidents tend to be famous and deadly. The Chernobyl accident may have killed more than 15,000 people. Three mile Island could have been deadly. No one knows what the long-term effects of the Fukushima meltdown will be.

Ironically, however, nuclear power is considered safe. The disasters make headlines, but yearly deaths from mining, burning, and drilling for oil and coal far exceed deaths related to nuclear power. Because nuclear power is so dangerous, the safety standards for most plants are extremely high.

Nuclear power is also relatively clean. It emits less carbon dioxide, contributing less to global warming than its competitors coal and oil. It's more efficient than any other power source. One ton of uranium produces as much energy as millions of tons of coal or oil. Therefore, nuclear power saves money and minimizes waste.

It sounds great, but that's not the whole story. Nuclear power's safety, first of all, is relative. While there have been very few nuclear accidents so far, they are always possible. A major accident at a nuclear plant would have far more devastating effects than a collapsed mine or a blown oil rig.

These potentially devastating effects mean nuclear power plants may become targets for terrorism. An attack on a nuclear plant could cripple an entire nation. It could even affect the whole planet.

Then there's the waste. Nuclear plants don't emit many gases, but they create radioactive waste. This waste must be stored away from humans for thousands of years, leaving a mess for other generations to clean up. This waste could also be used to make weapons.

Cheap and efficient, or deadly? Nuclear energy may be too powerful a process to ever be safe in human hands. Time— or the next disaster— will tell.

RP264 The Metal Eater

 RP264 The Metal Eater

My bike has been sitting outside in the rain for a week now. I know what I' ll find when the sun finally comes out and I can ride again: scratchy red rust.

Rust is a sign of corrosion. Corrosion is the process of a metal breaking down, separating into its different atoms. What was once a solid piece of steel is turned by corrosion into iron oxide and hydroxide. These are the red, spreading stains you can see.

The corrosion that creates rust is a chemical reaction between iron and oxygen. Water acts as a catalyst, the kick start for the reaction, because water helps the oxygen get into the metal particles.

A drop of rain falls on the metal chain on my bike. As soon as the water makes contact with metal, the metal begins to oxidize. The acid dissolves the iron in the metal. As that happens, the water is broken down into its two parts, hydrogen and oxygen. Some of the free oxygen combines with the iron to form the red, fragile iron oxide or hydroxide. If salt is present, the process happens even faster. Salt water helps the chemicals break down and move faster, which is why metal in seawater rusts away so quickly.

The type of rust formed will depend on the conditions. Iron hydroxides are formed by more pure combinations of metal, oxygen, and water. These rusts stick to the surface of the metal, but protect the metal underneath from rusting more. But when other chemicals come into play, the rust formed can be iron oxides. These flake off and blow away, leaving new metal constantly exposed. This destructive type of rust can eat entirely through a piece of steel.

Rust is preventable. The easiest way to keep metal from rusting is to put a barrier between it and the environment. This barrier can be paints, waxes, or oils.

That reminds me: I need to oil my bike!

RP248 Shampoo-Do We Really Need It

 RP248 Shampoo-Do We Really Need It?

We wash our hands with soap, brush our teeth with toothpaste, and clean our hair with shampoo. That's the way it's always been, right? Well... maybe not.

Shampoo, as we know it, is only about 100 years old. Before that, people washed their hair with soap once or twice a month. Shampoo has been marketed successfully, but many people now think it isn't good for us. They say shampoo is actually bad for your hair and your scalp. A few key ingredients in shampoo may be the culprits.

Shampoos almost always contain alcohol. The alcohol dries out both your hair and your scalp, eroding a natural oil barrier and leaving you potentially more vulnerable to bacteria. The reason we need conditioner after shampoo is to replace the oil that alcohol strips away. Mineral oil is generally used to make shampoos more gentle, but it can clog pores and cause acne and other skin problems. Sodium lauryl sulfate and sodium lauryl sulfate (SLS, SLES) are cleansers. They make shampoo form bubbles, or lather. Both strip dirt from hair, but both also cause skin irritation. Many natural health activists say SLS and SLES cause eye damage, skin damage, and hormone changes.

Unwashed hair gets greasy, of course. So how should we clean our hair? First, you need to give your hair a few weeks to adjust to the no-shampoo routine. The drying effect of shampoo causes our scalps to produce more oil, leading to greasy hair. When we stop stripping our scalps of oil, however, they will stop overproducing it, and our hair will achieve a balance. After that, hair can be washed occasionally with gentler soaps like baking soda or apple cider vinegar. They say often all we need is to scrub our scalps with water and brush a powder through dry hair to soak up excess oil.

Many people who have stopped shampooing say their hair is more beautiful and more manageable than ever before. Perhaps shampoo really is a sham.

RP232 The Accidental Savior

 RP232 The Accidental Savior

Nowadays, if you cut your hand, you wash it with soap and water, put a bandage on it, and forget about it. You don't worry about developing a fatal infection. If you get a sore throat that doesn't go away, you go to the doctor and get an antibiotic. Minor illnesses don't scare us anymore, thanks to Alexander Fleming and his famous discovery—penicillin.

Before the 1940s, any infection could be fatal. Scarlet fever was a killer. Simple bacterial infections spread to the blood, bones, and brain, and easily turned deadly. Soldiers fighting in World War I feared gangrene (a wound infection) as much as enemy weapons.

Fleming had seen WWI soldiers die from infected wounds but also from dangerous, ineffective treatments. He was driven to find a cure for infections. In 1928, he was researching the bacteria staphylococcus. He went on vacation, leaving the petri dishes containing the bacteria in his laboratory. When he returned, one of them was contaminated with mold, and the mold had killed the surrounding bacteria!

Fleming spent the next twelve years studying that mold, from the genus Penicillium. It produced a chemical that killed many disease-causing bacteria. This substance was called "penicillin" by Fleming. Finally, Howard Florey and Ernst Chain, among many other scientists, helped create a substance that could be mass produced.

Governments saw how significant penicillin could be to the war effort and helped support its production. Scientists raced to produce penicillin knowing they could save thousands of soldiers' lives by killing infections in their wounds. Penicillin is sometimes seen as a secret weapon of WW II.

Even at home, away from the fighting, the demand for penicillin was instant. Lives changed almost overnight. The fear of death by a simple infection was erased, and many childhood illnesses became merely inconvenient, rather than life-or-death struggles. Today, we live without worrying that our next scratch or cough might be our last.

RP218 The Great Connector Collagen

 RP218 The Great Connector: Collagen

browse the beauty aisle of a pharmacy and you' ll see it on every other lotion or potion bottle: collagen. There are collagen pills and collagen creams. Doctors give collagen injections. What is collagen, and why is it everywhere?

Collagen is a kind of protein found in animals. We' re full of it. It makes up 25 percent or more of the protein in our bodies. It's in our muscles, tendons, ligaments, cartilage, bones, corneas, blood vessels, teeth, and especially skin. Our skin, without its water, is about 80 percent collagen.

Collagen is extremely strong and usually fibrous, meaning it forms long, thin, stringy shapes. Collagen, therefore, is crucial to our bodies' connections. It provides much of the structure of our bodies, linking organs, muscles, and bones. Its flexibility helps our bodies move and stretch.

It's the collagen in our skin that's in the news nowadays. Collagen (with elastin, another protein) is what makes our skin firm, tight, and elastic. It provides our skin's structure and flexibility. As we age, collagen production slows, and the collagen in our skin starts to break down. Skin gets looser. Wrinkles appear. Skin is slower to move back into place after it's pulled away.

So collagen has become a cosmetic superstar. When injected into the skin, it plumps the skin up, reducing wrinkles. Bottles of collagen pills say they do the same thing. This is debatable because the pills are broken down in the stomach. Many skin creams contain collagen, but as skin doesn't seem to absorb collagen, they may not work either.

You can boost your collagen production. Some vitamins seem to promote it when used in creams. The vitamins can be absorbed through the skin. They then promote collagen production or slow its destruction. Eating well also helps. Eat fruits and vegetables while avoiding fats and toxins and your skin will thank you.