The other day I mentioned that I had added an index of 11th grade chemistry topics and that I was hyperlinking content so you could learn high school chemistry online. This has involved creating some new content for topics I normally wouldn't cover. The Bohr Model is a case in point. It's considered important for students to learn, but I personally feel it gives them the wrong idea about how electrons behave. They aren't out there happily circling the nucleus. I mean, they might be, but they could be passing through the nucleus or exist pretty much anywhere in the vicinity of the atom. The Bohr Model addressed fundamental flaws in the Rutherford model and successfully explained the Ryberg formula, but most students don't leave high school caring much about the spectral lines of hydrogen. They do have this notion about what an atom is and how it looks and behaves. Usually that is based on the Bohr Model. It's a good model and all... it's just not right.

July 14^th marks the passing of William Perkin. Perkin was an English chemist best known for starting the synthetic dye industry with his accidental discovery of the aniline dye mauveine. At 15 years old, Perkin was studying chemistry under the German chemist August Wilhelm von Hofmann. Hoffmann believed it was possible to synthesize the antimalarial drug quinine and set the young Perkin to the task. During one Easter break when his boss returned to Germany, Perkin continued his work at his home laboratory when one of his aniline mixtures produced a vivid purple color. He thought he had found something interesting, but it wasn't what his teacher wanted, so he kept his discovery to himself. He continued to test his new dye mixture with his friend Arthur Church and brother Thomas. They found the dye was stable after washing and long exposures to light and sent samples to textile mills to get the opinions of experts. Dyes at this time were from natural products that were expensive to produce. A relatively inexpensive source of fabric coloring could have profound commercial success.

Perkin filed a patent for his dye and called it mauveine when he was only 18 years old. Using capital from his father, he found a way to produce his dye in quantity and cheaply. His business took off on a grand scale, making the young Perkin extremely wealthy and began a new industry in Europe.

Find out what else occurred on this day in science history.

If you're taking chemistry in high school it doesn't have to be in the 11th grade, but it seems like most schools offer 10th grade biology, 11th grade chemistry, and 12th grade physics. There are a lot of topics covered in 11th grade chemistry. For the most part these are the same concepts as you'll see if you take college chemistry, though sometimes 11th grade chemistry doesn't quite make it to nuclear chemistry or introductory physical or organic chemistry. Also, college chemistry covers more about qualitative and quantitative analysis.

Anyway... here's a typical list of 11th grade chemistry topics. I've been going through adding links to online coverage of each topic. I'm adding additional pages that focus specifically on the topics, so when I'm doing linking the page will essentially be a high school chemistry textbook, except online and without those really comfortable lab bench stools.

July 13^th marks the passing of Friedrich August Kekulé von Stradonitz. Kekulé was a German theoretical chemist who figured out how carbon atoms could have a valence of 4 and join together to make long isomers or even rings. He was the first to discover the ring structure of benzene and greatly advanced the understanding of organic chemistry and aromatic compounds of the time.

Kekulé wrote about the method of his discovery where he was sitting by the fireplace and started to nod off. He dreamed of atoms arranging themselves in groups of ever increasing size until they became long chains. The chains started to wind and turn like snakes until one snake grabbed its own tail. He woke up suddenly and spent the rest of the night working out the structure.

It just goes to show that if you let your mind wander, you may figure out a solution to a problem. That, or it shows chemists can have some strange dreams. Find out what else occurred on this day in science history.