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What’s the Difference Between a Stalactite and a Stalagmite?

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Well-meaning geologists ended up confusing plenty of folks when they named stalactites and stalagmites. Both of these similar-sounding structures—typically formed in limestone caves—are capable of stretching over 27 feet in length. But what's the difference between them, and how do such strange ornaments grow in the first place?

Let’s clear up the terminology. Here’s a helpful (and widely-used) phrase you can use to sort out which is which: “Stalactites hold tight to the ceiling and stalagmites might touch the ceiling.” In other words, stalactites form on the roofs of caves and dangle downward like rocky icicles. Stalagmites, in contrast, are based on the floor and stretch upwards, only occasionally coming into contact with the overhanging ceiling.

An alternate memorization method goes as follows: “stalactite” is spelled with a “t,” as in “top.” “Stalagmite” uses the letter “g," as in “ground.”

According to the Oxford English Dictionary, these two terms descended from the Greek word stalaktos, which means “to drip." This is because trickling rainwater is responsible for the conical objects’ formation. When rain seeps through limestone, the water extracts carbon dioxide gas from the rock. What results is a weak carbonic acid that penetrates the stone and deposits a patch of calcite on the caves’ roof. As the water continues dripping, more and more calcite is added to the spot, eventually producing a lengthy stalactite.

But what about stalagmites? There’s a reason these are generally found directly underneath stalactites—all that dripping water has to land somewhere, after all. When a drop finally hits the cave floor, it deposits even more calcite there, this time in an unassuming mound. The liquid keeps dripping off the tip of a stalactite and the lump keeps rising, leaving us with a surging stalagmite. To call this process gradual would be a gross understatement. In limestone caverns, the usual growth rate is under 10 centimeters per millennium. 

It’s also worth noting that both stalagmites and stalactites belong to a larger geological group known as “speleothems." This is an extensive family of differently-shaped mineral formations that also includes globular “cave popcorn” and stunningly-beautiful “flowstones." Additionally, lava is occasionally involved in stalactite creation, leading to some strange-looking results. 

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Big Questions
What Is the Difference Between Generic and Name Brand Ibuprofen?
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What is the difference between generic ibuprofen vs. name brands?

Yali Friedman:

I just published a paper that answers this question: Are Generic Drugs Less Safe than their Branded Equivalents?

Here’s the tl;dr version:

Generic drugs are versions of drugs made by companies other than the company which originally developed the drug.

To gain FDA approval, a generic drug must:

  • Contain the same active ingredients as the innovator drug (inactive ingredients may vary)
  • Be identical in strength, dosage form, and route of administration
  • Have the same use indications
  • Be bioequivalent
  • Meet the same batch requirements for identity, strength, purity, and quality
  • Be manufactured under the same strict standards of FDA's good manufacturing practice regulations required for innovator products

I hope you found this answer useful. Feel free to reach out at www.thinkbiotech.com. For more on generic drugs, you can see our resources and whitepapers at Pharmaceutical strategic guidance and whitepapers

This post originally appeared on Quora. Click here to view.

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Big Questions
Do Cats Fart?
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Certain philosophical questions can invade even the most disciplined of minds. Do aliens exist? Can a soul ever be measured? Do cats fart?

While the latter may not have weighed heavily on some of history’s great brains, it’s certainly no less deserving of an answer. And in contrast to existential queries, there’s a pretty definitive response: Yes, they do. We just don’t really hear it.

According to veterinarians who have realized their job sometimes involves answering inane questions about animals passing gas, cats have all the biological hardware necessary for a fart: a gastrointestinal system and an anus. When excess air builds up as a result of gulping breaths or gut bacteria, a pungent cloud will be released from their rear ends. Smell a kitten’s butt sometime and you’ll walk away convinced that cats fart.

The discretion, or lack of audible farts, is probably due to the fact that cats don’t gulp their food like dogs do, leading to less air accumulating in their digestive tract.

So, yes, cats do fart. But they do it with the same grace and stealth they use to approach everything else. Think about that the next time you blame the dog.

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