Happy Birthday Antoine Lavoisier

Antoine Lavoisier, born August 26, 1743, French chemist and one of the fathers of modern chemistry.  He brought chemical experimentation from the philosophical alchemists to the scientific chemists.  He stated the first version of the law of conservation of mass, co-discovered, recognized, and named oxygen (1778), as well as hydrogen, disproved the phlogiston theory, introduced the metric system, wrote the first extensive list of elements, and helped to reform chemical nomenclature all before being beheaded on 8 May 1794 in Paris, at the age of 50.

Happy Birthday Amedeo Avogadro

Amedeo Avogadro, born August 9, 1776, was an Italian chemist known for his work on the theory of molarity and molecular weight.  While he didn’t discover the number of particles in one mole of a substance, 6.022×10²³, is now know as Avogadro’s number.

(edit:spelling)

I have Mass. You have Mass...

Man: I have mass.  You have mass.  We are naturally attracted.
Woman: It's a purely physical attraction.

Happy Birthday Rosalind Elsie Franklin

Rosalind Elsie Franklin, born July 25, 1920, was a Physical chemist and crystallographer who worked on the X-ray diffraction images of DNA which formed a basis of Watson and Crick's hypothesis of the double helical structure of DNA in their 1953 publication.  When published in its own article along side Watson and Crick’s, her data constituted critical evidence of their hypothesis.  Later, she led pioneering work on the tobacco mosaic and polio viruses.

Test Tube Science: Black Bean Indicator

There are lots of acid/base indicators available in the home.  The one I'm going to talk about today is an indicator made from black beans.

Marcelle was making a big batch of feijoada and started the black beans soaking the night before we were going to have it for dinner.  As she was preparing to pour off the blue/purple water they had soaked in I asked her to save some for me.

The dinner was delicious. And I decided that I'd see what colors I could come up with after dinner.  In the picture below you can see the spectrum of colors obtained from my black bean juice with vinegar and baking soda.

Black bean indicator: acidic on the left, neutral in the middle and basic on the right.

To make your own indicator take 10-15 dry black beans put them in a test tube and cover them with water.  Let them soak for 10-12 hours for the most concentrated solution.  Now you can remove the water and use it as an indicator in other solutions.  Dilute the black bean juice 1 part juice to 4 parts test solution.

If you want to get some indicator in 10 minutes instead of 10 hours you can soak the beans in 70% isopropyl alcohol.  The alcohol will make a solution much faster.

Acid, neutral, and basic forms of anthocyanins.

The primary color changing molecules in black beans are anthocyanins. As the pH of the solution changes the structure of the molecule changes.  This changes its absorption spectrum thus changing the color of the solution. These reactions are in equilibrium making them great natural indicators.

U and I Together

Man: If I were designing the periodic table I'd put U and I together.
Woman: A then both Mendeleev and I would cry.

Happy Birthday Emil Erlenmeyer

Emil Erlenmeyer, born June 28, 1825, is the inventor of the conical flask which bears his name.

Wanted Dead and Alive

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Happy Birthday Dorthy Mary Crowfoot Hodgkin

Dorothy Mary Crowfoot Hodgkin, born 12 May 1910, was a British founder of protein crystallography. She pioneered the technique of X-ray crystallography, a method used to determine the three dimensional structures of molecules. Among her most influential discoveries are the determination of the structure of penicillin, insulin, and vitamin B12 for which she was awarded the Nobel Prize in Chemistry. In 1969, after 35 years of work, Hodgkin was able to decipher the structure of insulin. She is regarded as one of the foremost scientists in the field of X-ray crystallography of natural molecules.

Eat. Sleep. Chemistry.

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