World's Roundest Object!

Be careful when discussing this video with your students. This is about the world's roundest sphere...sphere. It's not a ball. It's a sphere.

Just saying.

'Cause I know I've said ball in front of my high school students, and it took me a while to get the boys' attention back.

(In a related aside, my wife is listening in as this video plays. She lost control at 6:22 when the narrator said "Newtons, Joules". To quote her: "heh, heh...Newton's jewels...heh, heh".)

This 'world's roundest object' is more about the basis of our metric (now the systemé international d'unités or SI) than it is about materials science. There are, however, some serious challenges involved in making a material that won't decompose, that won't get dirty, that won't wear away, that won't change over time.

Here they have created - according to the scientist at 7:25 - a single crystal of silicon with 'no voids or dislocations' and containing only one isotope of silicon, making the material just slightly less valuable than absolutely, perfectly, priceless.