Upside Down Christmas Tree.

I rather dislike the "centrifugal force is not a thing." It certainly is a thing, and has many practical uses in analyzing various situations. The only problem is that such inertial forces that come about from being in an accelerating frame have some caveats and are easy to make simple mistakes with. Some care needs to be taken when teaching circular motion, to make sure students learn the actual concepts and not something superficial. But somehow this has evolved into the idea that "centrifugal force does not exist" instead of "centrifugal force is handled differently than what was previously covered." Not surprisingly, people don't seem to attack the Coriolis force, despite being another fictitious force just like the centrifugal force.

Wow, neat! I never knew that glass wasn't a solid... You know, I've always been fascinated by moldavite, it being millions of years old (and so pretty :D ). It's basically naturally occurring glass (like, say, obsidian), and you can pinpoint its origin quite exactly because all of it on this planet only exists courtesy of this one distinct meteor impact. But now I appreciate it a lot more, knowing that it's somehow solid and liquid at the same time (or maybe neither).

Looking further into it that also explains to me the difference between glass and rock crystal, which as a quartz would indeed be a strictly solid form of glass. I've really learned something today!

I used the 'correlation does not imply causation' in an English essay and my teacher made me explain to her what I meant