Wednesday, April 7, 2010

This Day in Science History - April 7 - World Health Day

April 7th is World Health Day. World Health Day is sponsored by the World Health Organization to promote awareness of a specific theme of concern for WHO. The 2010 theme is '1000 Cities, 1000 Lives'. They are collecting 1000 stories of people contributing to health awareness and profiling 1000 cities around the world that promote health or cleanup campaigns.

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

1823 - Jacques-Alexandre-C├ęsar Charles died.

Charles was a French physicist and inventor who described the relationship between the volume and absolute temperatures of ideal gases known as Charles's Law. He also built the first hydrogen filled balloon and the first manned hydrogen filled balloon.

1817 - Francesco Selmi was born.

Selmi was an Italian chemist who was a pioneer in colloid chemistry. He also coined the term 'ptomaine poisonoing' while studying putrification and poisons.

Scientists Discover a New Element - First Atoms of Element 117 Produced

When you go looking for new elements, you already know how many protons they are going to have. It's a matter of finding the new element, making it, or detecting decay products that could only have come from the new element. This is a tricky process because the higher atomic weight elements are difficult to produce and very, very short-lived. It's rare for new elements to be discovered, so I'm excited that a team of Russian and American scientists report that they have created 6 atoms of element 117. Atoms of the new element were produced by firing atoms of calcium (atomic number 20) at a berkelium target (atomic number 97) to produce atoms with 117 protons.

At this time, no 'real' name for element 117 has been proposed, so you can call it element 117 or by its placeholder name, ununseptium (which means 117). Names are proposed for elements only after their existence has been confirmed by a second source. The New York Times has more details about the discovery or you can read the report of the element's production in Physical Review Letters.

Tuesday, April 6, 2010

Who Invented the Periodic Table?

Question: Who Invented the Periodic Table?

Do you know who described the first periodic table of the elements that ordered the elements by increasing atomic weight and according to trends in their properties? I'll give you a hint. It was not Dmitri Mendeleev. The actual inventor of the periodic table is someone rarely mentioned in chemistry history books.

Answer: If you answered "Dmitri Mendeleev" then you might be incorrect. Dmitri Mendeleev presented his periodic table of the elements based on increasing atomic weight on March 6, 1869, in a presentation to the Russian Chemical Society. While Mendeleev's table was the first to gain some acceptance in the scientific community, it was not the first table of its kind.

John Newlands had published his Law of Octaves in 1865. The Law of Octaves had two elements in one box and did not allow space for undiscovered elements, so it was criticized and did not gain recognition.

What Is Distillation?

Question: What Is Distillation?

Answer: Distillation is a widely used method for separating mixtures based on differences in the conditions required to change the phase of components of the mixture. To separate a mixture of liquids, the liquid can be heated to force components, which have different boiling points, into the gas phase. The gas is then condensed back into liquid form and collected. Repeating the process on the collected liquid to improve the purity of the product is called double distillation. Although the term is most commonly applied to liquids, the reverse process can be used to separate gases by liquefying components using changes in temperature and/or pressure.

Distillation is used for many commercial processes, such as production of gasoline, distilled water, xylene, alcohol, paraffin, kerosene, and many other liquids. Types of distillation include simple distillation (described here), fractional distillation (different volatile 'fractions' are collected as they are produced), and destructive distillation (usually, a material is heated so that it decomposes into compounds for collection).

Who Was the First Chemist?

Question: Who Was the First Chemist?

Chemistry has been around for a very long time! Do you know the name of the first chemist in recorded history? Would it surprise you that the first chemist was a woman?

Answer: The first known chemist was a woman. A Mesopotamian cuneiform tablet from the second millenium B.C. describes Tapputi, a perfumer and palace overseer who distilled the essences of flowers and other aromatic materials, filtered them, added water and returned them to the still several times until she got just what she wanted. This is also the first known reference to the process of distillation and the first recorded still.

How to Get Mosquitoes to Bite Your Friends

... not that actually want mosquitoes to bite your friends, but I think you will agree you don't want to be bitten. Here's a list of things that attract mosquitoes. If you want to avoid an encounter with the vampiric swarm you can avoid doing any of these things yourself or you can encourage those around you to do them. Whatever works.

Wear Dark Clothing

Many mosquitoes use vision to locate hosts from a distance. Dark clothes and foliage are initial attractants.


You give off more carbon dioxide when you are hot or have been exercising. A burning candle or other fire is another source of carbon dioxide.

Eat Bananas and French Fries

You release more lactic acid when you have been exercising or after eating certain foods (e.g., salty foods, high-potassium foods).

Wear Perfume or Cologne

In addition to perfumes, hair products, and scented sunscreens, watch for the subtle floral or fruity fragrances from fabric softeners and dryer sheets.

Have Cold Hands

Mosquitoes are attracted by a particular temperature range. The exact temperature depends on the type of mosquito. Many mosquitoes are attracted to the slightly cooler temperatures of the extremities.

Perspire, Swim, or Play in the Sprinkler

Mosquitoes are attracted by perspiration because of the chemicals it contains and also because it increases the humidity around your body. Even small amounts of water (e.g., moist plants or mud puddles) will draw mosquitoes. Standing water also allows mosquitoes to reproduce.

I am a veritable mosquito magnet. I wear a lot of black, favor Coppertone™ when outdoors (bloodsuckers seem to love the subtle jasmine scent of that sunscreen), and can be found near the beach or poking at the barbeque, sipping a sports drink or fruity drink. Don't be like me! Or if you are, try one of these natural mosquito repellents.