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Science Over the EdgeA Roundup of Strange Science for the MonthApplet credit: Ed Hobbs
February 2004 |
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In the News:
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What's New at the Museum:
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Ask the Curator:
This is just one of those questions that begs for a diagram, so after you read the text, click here. As you are probably aware the moon orbits the Earth roughly once a month. The Earth, in turn rotates once every twenty-four hours. The side that faces the sun is in daylight, the side away from the sun is in night. Since the moon moves around the Earth it can be overhead in the sky anytime of the day or night depending on where it is in it's orbit. Because the moon is lit by reflected sunlight it will, in general, be more "full" and brighter in the night sky and less "full" and dimmer (and therefore less noticeable) in the day sky. When the moon is very close to the position of the sun in the sky it may not be visible at all. We associate the moon with the night because without the sun around it is the brightest thing in the sky. When it is up in the day it tends to get washed out and we don't often notice it.
A gizzard is a muscular pouch in the digestive system that allows birds and certain invertebrates to grind food down without using teeth. Usually the animal swallows small stones or grit to do the grinding. We know some dinosaurs had gizzards because we've found their gizzard stones within their fossilized remains. Spiders have lungs, but they aren't like ours. Some spiders have a trachea (a kind of tube) that does the job of breathing, others have "book-lungs." A few species of spiders have both. As for "daddy-long-legs," well, there are several animals with that name, but since we are talking about spiders I'll assume we are talking about daddy long-leg spiders (of which there are several species). Like all spiders they don't need a gizzard because they don't eat solid food. They kill their prey, liquefy them, then suck them dry. As spiders they would also have either the book-lung, trachea or both. There's also a creature known as a "harvestman" that has the common name "daddy longlegs." These look like spiders, but are not. I have to admit I'm not sure how their digestive system works, so if there are any readers out there who are experts on these animals, drop us a line.
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| In History:
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In the Sky:
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Observed:
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On the Tube: Currently we are only able to give accurate times and dates for these programs in the United States. Check local listings in other locations.
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LGM: Science over the Edge ArchivesLGM Archive 1998, 1999, 2000, 2001, 2002, 2003, 2004. Copyright Lee Krystek 2003. All Rights Reserved. |