One of the questions I had at the end of the Chemistry Basics II post was about how neurons were discovered. I guess these two channels have become my go to sources for these explanations. The Chadwick and the Neutron video presents a bit more history (e.g. the involvement of Marie Curie’s daughter).
chadwick and the neutron
I like the next video because it poses several questions that should be hints that the model without neutrons.
Atomic Structure: Discovery of the Neutron
The use of radiation in these experiments naturally raises the question of how these various types of radiation were discovered. Kathy Loves Physics addresses this in her video.
Chemistry Basics I covered the sections on scientific discovery up to atomic theory. Next is the question of what atoms are made of. Enter JJ Thomson with his CRT experiments. These 3 videos explain his discovery of the electron. I watched multiple just to see different perspectives on the same experiment.
It was after watching the next one that I found myself wondering how you pump all the air out of a glass bottle.
Discovery of the Electron: Cathode Ray Tube Experiment
JJ Thomson and the discovery of the electron
After it had been established that electrons exist and that they have negative charge, it naturally follows that we would want to know what the charge on an electron actually is. This was resolved by Millikan’s oil drop experiment.
This next video on the oil drop experiment was helpful because it showed a similar but modern setup.
The discovery of electrons, combined with the fact that matter is in general electrically neutron implies that there must be positively charged particles. Ernest Rutherford’s gold foil experiment confirms this:
At this point I have several questions that will have to wait for another time.
How are magnets made (e.g. the ones used by J.J. Thomson)?
How were alpha particles Rutherford was using discovered?
How was it shown that the electrons move around the nucleus?
It’s been over 20 years since I last studied chemistry. I started reading General Chemistry: Atoms First. It has an introductory chapter 0 that goes over concepts like fundamental units and conversion between units. A mention of the amount of volcanic material ejected into the atmosphere by the Krakatoa volcanic erruption piqued my curiosity enough to watch this History channel video.
Krakatoa: Devastating Explosion | How the Earth Was Made (S1, E3) | Full Episode | History
Digging into chapter one opened my eyes to the fascinating journey of many scientists through the centuries trying to understand the world, and more specifically, elements. Accounting for the similarities between many of the elements was an undertaking that got a breakthrough in Dmitri Mendeleev’s periodic table as explained in the next video.
The genius of Mendeleev’s periodic table – Lou Serico
Reading about the isolation of oxygen from mercury oxide by Joseph Priestley made me curious about how this was done. Thankfully, there are many informative videos on these topics. Here’s one on the isolation of oxygen.
The Discovery of Oxygen & Combustion 1946 Educational Film 76244
This video has left me wondering where HgO came from – was it a compound they used for something else?
Antoine Lavoisier soon afterwards demonstrated the law of mass conservation.
Joseph Proust followed with the law of definite proportions.
John Dalton capped off the line of inquiry with the law of multiple proportions.
Searching for Joseph Proust on YouTube leads me to this interesting video with some of this history.
The Creation of Chemistry – The Fundamental Laws: Crash Course Chemistry #3
I wish I had all these videos as a tool when I was learning chemistry years ago.
One of the key lessons from reading about oxidation was that Si has a key advantage over other semiconductors – it oxidizes much more readily thereby simplifying the development of insulation. I was looking up videos on the Deal-Grove oxidation model law when I stumbled into these videos by Chris Mack from a microfabrication course at the University of Texas at Austin using the same Microfabrication book I’m reading! It’s amazing how much free content there is out there.
Crystal defects play an important role in semiconductor fabrication. One type of defect is a Frenkel defect. Understanding such defects involves determining the vacancy concentration as given by Arrhenius function. I reviewed several videos to help me understand this equation:
Background Concepts
I took a detour to remind myself about activation energy, electron volts, and Boltzmann’s constant (all of which feature when studying Arrhenius function).
Line Defects
Another type of crystal defect is a line defect, e.g. edge dislocation. These videos contain additional information about edge dislocations.
Area Defects
A stacking fault is an extra plane of atoms. Some resources about stack faults:
Gettering is a process by which impurities and defects diffuse through the crystal (controlling where defects occur). This can be used to improve yield in semiconductor manufacturing as explained in this video:
The previous post outlined my introduction to materials science with interest stemming from applications in microfabrication. Reading section 2.2 of Fabrication Engineering at the Micro- and Nanoscale left me curious for more information about crystal structures. A YouTube search for “face centered cubic structure” led me to the videos below, which proved sufficient for gaining a basic understanding of crystal structures.
These are also discussed in section 2.2 of the text and are explained in these videos. Interestingly, neither of the videos mentioned the fact that the plane notation also denotes a vector (from the origin) that is perpendicular to that plane!