You are currently browsing the monthly archive for October 2007.
Are electrons particles, or are they waves? In some sense, the answer is – it depends. It depends on how you choose to look at it. Here’s a nice video that gives a sense of how quantum mechanics developed, from Bohr’s model of the atom, to the Heisenberg uncertainty principle, to Schrödinger’s equation.
The second video is a demonstration of the uncertainty principle using a laser, an adjustable slit, and a projection screen.
Below is a picture with Bohr, Heisenberg, Schrödinger, Plank, Einstein and a few other famous scientists from the 1927 Solvay conference.
It has been pointed out that the alkali metal explosions video has some fakery in it. Specifically, both the rubidium and cesium explosions are regular, garden variety bombs, and not 2 g each of Rb and Cs. Apparently, it is actually quite difficult to get Rb and Cs to cause explosions. Check out this site, with videos of Li – Cs reacting with water.
Perhaps the folks at Braniac knew this, and wanted more spectacular demonstrations. Shame on them. Thanks to commenter Mitch, from the Chemical Forums Blog for pointing this out.
Note, even though these are faked in the video, we still won’t be doing them in lab any time soon…
Next week we will start an in-depth discussion of the electronic structure of atoms, and resulting periodic properties. This video might prime the pump. Enjoy!
Well it’s gone from youtube, but not metacafe…
Can you sing it?
‘Tis the season – for Nobel prize announcements. This year’s Nobel prize in Chemistry was awarded to Gerhard Ertl, who took the guess work out of finding catalysts. Elsewhere, the 2007 IgNobel prize (for scientific work that should never have been pursued) in Chemistry went to Mayu Yamamoto who found out how to extract vanillin flavoring from cow dung.
Where do the atoms in your body come from? Stars! Next week we will begin to discuss the nuclear reactions in stars that lead to the formation of the naturally occurring elements. Here is a video from Nova to tide you over during fall break.
The first step is hydrogen fusing to form helium. As hydrogen burns, carbon forms. Eventually even heavier elements are formed.
How do we know the elements are being formed in stars? Spectroscopy! (The universal fingerprint identifier). In this video, some scientists use absorption spectroscopy to identify elements in a supernova.
Word to your mother.
This movie provides a good visual of Le Châtelier’s Principle.
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