How Everything Works Questions and answers about the physics of everyday life http://www.howeverythingworks.org Copyright 2009, Louis Bloomfield en-us lab3e@virginia.edu (Lou Bloomfield) Thu, 11 Mar 2010 10:00:01 EST Thu, 11 Mar 2010 10:00:01 EST 60 http://blogs.law.harvard.edu/tech/rss What happens to the wax when a candle burns? A candle's wax doesn't simple transform into a liquid, it also vaporizes into a gas and that gas burns in air to become water vapor and carbon dioxide. Thu, 01 Oct 2009 11:27:31 EDT lab3e@virginia.edu (Lou Bloomfield) http://www.howeverythingworks.org/page1.php?QNum=1583 http://www.howeverythingworks.org/page1.php?QNum=1583 Why does combining red, green, and blue light create white light? Our eyes sense color by measuring the relative brightnesses of the red, green, and blue portions of the light spectrum. When all three are present, we perceive white. Fri, 17 Apr 2009 07:48:27 EDT lab3e@virginia.edu (Lou Bloomfield) http://www.howeverythingworks.org/page1.php?QNum=1582 http://www.howeverythingworks.org/page1.php?QNum=1582 Does removing two tubes in a four-tube fluorescent fixture save energy? Most four-tube fluorescent fixtures can operate with only two tubes and will consume only half as much energy. If you don't need the light, remove the tubes. Tue, 07 Apr 2009 14:36:35 EDT lab3e@virginia.edu (Lou Bloomfield) http://www.howeverythingworks.org/page1.php?QNum=1581 http://www.howeverythingworks.org/page1.php?QNum=1581 How can I describe a polymer to a group of 4th grade students? Polymers are giant molecules formed by sticking together many small molecules. They're properties depend on how they're assembled. Thu, 02 Apr 2009 09:16:36 EDT lab3e@virginia.edu (Lou Bloomfield) http://www.howeverythingworks.org/page1.php?QNum=1580 http://www.howeverythingworks.org/page1.php?QNum=1580 If a microwave oven door reflects microwaves, why doesn't everything? The door of a microwave oven is specially designed to reflect microwaves, while most objects in our environment are not. Tue, 31 Mar 2009 09:33:03 EDT lab3e@virginia.edu (Lou Bloomfield) http://www.howeverythingworks.org/page1.php?QNum=1579 http://www.howeverythingworks.org/page1.php?QNum=1579 Do fluorescent lamps really use less energy than incandescent bulbs? Fluorescent lamps are between 4 and 6 times as energy efficient as incandescent lightbulbs and they last many times longer, too. It's time for incandescent bulbs to go. Fri, 27 Mar 2009 10:39:57 EDT lab3e@virginia.edu (Lou Bloomfield) http://www.howeverythingworks.org/page1.php?QNum=1578 http://www.howeverythingworks.org/page1.php?QNum=1578 Why does adding salt to water make an egg float? A hard-boiled egg weighs almost exactly as much as the water it displaces. By varying the density of that water slightly, you can make the egg float or sink. Thu, 26 Mar 2009 14:40:37 EDT lab3e@virginia.edu (Lou Bloomfield) http://www.howeverythingworks.org/page1.php?QNum=1577 http://www.howeverythingworks.org/page1.php?QNum=1577 Are microwave makers responsible to warn people about superheating explosions? Microwave ovens can superheat water when it is heated in a glass or glassed container. Highly superheated water can explode and cause serious burns. Thu, 26 Mar 2009 12:42:31 EDT lab3e@virginia.edu (Lou Bloomfield) http://www.howeverythingworks.org/page1.php?QNum=1576 http://www.howeverythingworks.org/page1.php?QNum=1576 Can you break a microwave oven by running it with nothing inside? Modern microwave ovens are pretty robust and they usually survive being run without anything inside them. It's not a great idea, but it's not always a disaster either. Thu, 19 Mar 2009 08:57:13 EDT lab3e@virginia.edu (Lou Bloomfield) http://www.howeverythingworks.org/page1.php?QNum=1575 http://www.howeverythingworks.org/page1.php?QNum=1575 Why are high heeled shoes so damaging to floors? High heeled shoes exert enormous pressures on the surfaces that support them and often damage wood floors as a result. Thu, 19 Mar 2009 08:39:28 EDT lab3e@virginia.edu (Lou Bloomfield) http://www.howeverythingworks.org/page1.php?QNum=1574 http://www.howeverythingworks.org/page1.php?QNum=1574 Can pulling a superlong string send signals faster than the speed of light? A long string connecting two planets can't send signals faster than the speed of light. In fact, it can't send signals faster than the speed of sound in that string. Wed, 18 Mar 2009 08:53:49 EDT lab3e@virginia.edu (Lou Bloomfield) http://www.howeverythingworks.org/page1.php?QNum=1573 http://www.howeverythingworks.org/page1.php?QNum=1573 Is it safe to locate my dog's bed near the power adapter for the telephone? Although the power adapter for a telephone produces electric and magnetic fields, they're mostly contained within it and there's no convincing evidence of any danger Mon, 16 Mar 2009 18:52:04 EDT lab3e@virginia.edu (Lou Bloomfield) http://www.howeverythingworks.org/page1.php?QNum=1572 http://www.howeverythingworks.org/page1.php?QNum=1572 How are the suffixes for websites determined? Whether a website ends with .com or .org or .in depends entirely on the people who create the website. They can choose whatever they like. Thu, 12 Mar 2009 09:56:21 EDT lab3e@virginia.edu (Lou Bloomfield) http://www.howeverythingworks.org/page1.php?QNum=1571 http://www.howeverythingworks.org/page1.php?QNum=1571 Is it safe to operate a microwave oven with a broken window? The front window of a microwave oven supports the metal grid that forms the sixth side of the cooking chamber. Operating the oven with a broken window is a bad idea. Thu, 12 Mar 2009 09:23:35 EDT lab3e@virginia.edu (Lou Bloomfield) http://www.howeverythingworks.org/page1.php?QNum=1570 http://www.howeverythingworks.org/page1.php?QNum=1570 Is it safe to turn off computer equipment by turning off the power strip? As long as you shut down your computer first, switching off the power strip is a good way to ensure that your computer equipment isn't wasting electric power. Wed, 11 Mar 2009 09:31:24 EDT lab3e@virginia.edu (Lou Bloomfield) http://www.howeverythingworks.org/page1.php?QNum=1569 http://www.howeverythingworks.org/page1.php?QNum=1569