To witness the incredible power of steam, you don't have to look any further than the eruption of geysers or the explosion of gasses that occurs when lava reaches the ocean. Early man witnessed such sights and has long sought to control the raw power of steam through technology ranging from the basic tea kettle to the modern nuclear power plant.
Regardless of the level of technology involved, steam power comes down to one basic principle: When water is heated to the point of vaporizing, the vaporized water takes up more space than the liquid water did. This is because solids, liquids and gases are each held together by different levels of molecular forces. In solids, the molecules are compact. In liquids, they're further apart. And in gasses, like steam, they're even further apart.
If you heat a can of soup in a fire, the liquid contents will vaporize and eventually expand to the point where the can will explode to release the pressure inside. When this pressure is used to perform a particular task -- like turning a turbine or causing a kettle to whistle -- steam technology is harnessing steam power. The methods of heating, containing, channeling and using steam have changed, but the basic principle remains the same.
Learning to harness the power of steam has been a long process. Greek mathematician Hero theorized the use of steam technology in the second half of the first century. However, it would be well over 1,600 years before the first practical steam engine was created in order to drain water from mines and gardens. The age of steam that followed shaped the course of history by powering the Industrial Revolution, transforming the global shipping industry and revolutionizing modern warfare.
In this article, we'll look at how steam technology developed over the centuries and how our understanding of steam power changed the world.
Sunday, March 1, 2009
Is insulation dangerous?
Is insulation dangerous?Rummaging around in your friend's newly renovated attic, you notice what looks like a rolled-up blanket in the far corner. You give it a kick, and the blanket unfurls onto the floor. It's pink, and the material looks a little like cotton candy. You run your hand over it to see what it feels like, but you soon realize that was a mistake. Before you know it, your hand is red and itchy -- you've just come in contact with fiberglass insulation.
Insulating our homes is one of the most important parts of house construction, and insulation has a big effect on the costs of energy. Heat naturally flows from a warm space to a cool space, and our homes suffer from this transfer. In the winter, warm air from the inside will move to the outside and make us cold. In the summer, hot air moves from the outside to the inside and makes it uncomfortably warm.
We have heating and air conditioning systems to fix these problems, but the more opportunities warm air has to flow out of or into the house, the harder those systems have to work. As those systems work harder, we use more energy and pay much higher utility bills. A properly insulated home will save money on energy costs by resisting the flow of heat and making your heating and air conditioning work less.
Fiberglass insulation, a man-made mineral fiber constructed from a variety of materials, such as sand and recycled glass, is the most popular form of insulation in the United States -- more than 90 percent of homes in America are lined with the pink stuff [source: The Environmental Magazine]. But while many see the benefits of insulating our houses with fiberglass, some are worried fiberglass can cause various health problems -- it's capable of causing immediate skin irritation, and some researchers fear inhaling fiberglass particles could cause cancer.
Insulating our homes is one of the most important parts of house construction, and insulation has a big effect on the costs of energy. Heat naturally flows from a warm space to a cool space, and our homes suffer from this transfer. In the winter, warm air from the inside will move to the outside and make us cold. In the summer, hot air moves from the outside to the inside and makes it uncomfortably warm.
We have heating and air conditioning systems to fix these problems, but the more opportunities warm air has to flow out of or into the house, the harder those systems have to work. As those systems work harder, we use more energy and pay much higher utility bills. A properly insulated home will save money on energy costs by resisting the flow of heat and making your heating and air conditioning work less.
Fiberglass insulation, a man-made mineral fiber constructed from a variety of materials, such as sand and recycled glass, is the most popular form of insulation in the United States -- more than 90 percent of homes in America are lined with the pink stuff [source: The Environmental Magazine]. But while many see the benefits of insulating our houses with fiberglass, some are worried fiberglass can cause various health problems -- it's capable of causing immediate skin irritation, and some researchers fear inhaling fiberglass particles could cause cancer.
Why is it so hard to quit smoking?
Most regular smokers will agree that a cigarette after a meal is one of life's simple pleasures. Same with the wake-up smoke, the work-break smoke, the stress smoke and the morning coffee smoke. While smokers will list a variety of reasons why they continue to smoke despite the fact that half of them will die younger because of it, the real truth can largely be boiled down to one fact -- they're addicted to nicotine. Most people know the word, but many may not actually know what it is. Here's the skinny: Nicotine is a naturally occurring colorless liquid in tobacco that turns brown when burned.
There's technology out there to remove most traces of nicotine from cigarettes. But tobacco companies don't just ignore this fact -- they go out of their way to enrich the addictive properties of nicotine. There are eight patented ways to increase nicotine content by adding it to the tobacco after it's harvested. Five of them work to add nicotine to filters and wrappers. Another 12 are used to develop advanced technology to manipulate nicotine levels and develop new chemical variants.
It's no wonder that two-thirds of adult smokers who wish they could quit say they aren't able to. It shouldn't be a surprise that only one in 10 smokers can kick the habit. A startling 50 percent of people who have surgery for lung cancer recover and reach for the pack again [source: FDA]. A cigarette contains about 2 mg of nicotine. A pack-a-day smoker delivers about 250 hits of nicotine to his or her brain each day [source: NIDA]. So quitting isn't just about that one pack, it has more to do with those 250 hits. This helps explain why it's so hard to quit. So does your gender, your genes, what brand you smoke and whether or not you suffer from a mental illness.
There's technology out there to remove most traces of nicotine from cigarettes. But tobacco companies don't just ignore this fact -- they go out of their way to enrich the addictive properties of nicotine. There are eight patented ways to increase nicotine content by adding it to the tobacco after it's harvested. Five of them work to add nicotine to filters and wrappers. Another 12 are used to develop advanced technology to manipulate nicotine levels and develop new chemical variants.
It's no wonder that two-thirds of adult smokers who wish they could quit say they aren't able to. It shouldn't be a surprise that only one in 10 smokers can kick the habit. A startling 50 percent of people who have surgery for lung cancer recover and reach for the pack again [source: FDA]. A cigarette contains about 2 mg of nicotine. A pack-a-day smoker delivers about 250 hits of nicotine to his or her brain each day [source: NIDA]. So quitting isn't just about that one pack, it has more to do with those 250 hits. This helps explain why it's so hard to quit. So does your gender, your genes, what brand you smoke and whether or not you suffer from a mental illness.
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