Posts

Showing posts from April, 2010

This Day in Science History - April 17 - Giovanni Riccioli

The Moon has its own unique geography. We have names for the smooth dark areas like Mare Serenitatis and Mare Tranquillitatus, otherwise known as the Sea of Serenity and Sea of Tranquility. The craters have names like Tycho, Copernicus and Archimedes. One man is largely responsible for these names, Giovanni Riccioli celebrates his birthday today. Riccioli was one of the most prominent astronomers of his time and created a detailed atlas of the Moon. His names for the Maria and craters have lasted to current times.

Do Goldfish Turn White in the Dark?

Image
My kids were making dinner the other night and asked me about a fun fact they read on the side of a box of fish filets. The 'fact' said goldfish kept in the dark will turn white. Both the chemistry and biology of fish color are pretty complex. Fish color can change in response to their environment (including lighting), heredity, diet, age, and other factors. The color changes range from temporary to permanent. The fun fact was an oversimplification. Your goldfish would become pale from lack of light, but unless you either starve it or feed it foods lacking pigments, it won't turn white. Learn more about goldfish colors...

Why Students Fail Chemistry

The semester is nearing its end at many schools. Are you concerned you may not pass your chemistry class? It's not too late to learn the concepts or to make a change in your study habits. Knowing reasons why students fail may help you avoid making the same mistakes. Top Ways to Fail a Chemistry Class Avoid these mistakes to help ensure success in your chemistry class. 1. Don't Show Up Possibly one of the easiest ways to ensure failure is to not attend class. It's possible to teach yourself chemistry without ever setting foot in a classroom, but learning a subject isn't the same as passing a class. If you don't put in the time, you probably won't know what is expected of you for exams. You won't know what problem sets are due. You can't do labs if you aren't there. Even if there isn't an attendance policy, it helps to put in face-time .

Do Debbie Meyer and Evert Fresh Green Bags Work?

Debbie Meyer Green Bags and Evert-Fresh Green Bags are a storage product advertised as capable of keeping produce fresh for up to 30 days. They are plastic bags that contain zeolite that absorbs ethylene gas. Plants use ethylene as a hormone. One of its actions is to ripen fruit, so if you can reduce the concentration of ethylene around an apple, for example, it shouldn't get over-ripe and mushy as quickly. Do Green Bags work? Well... they probably do lower the levels of ethylene inside the plastic bag, so if you are comparing how long fruits and vegetables stay fresh in Green Bags as compared with other plastic bags, you might see an improvement. Or you might not, since ripening is not necessarily why produce spoils. Strawberries and raspberries, for example, usually mold long before the fruit itself goes bad. Most produce really shouldn't be stored in plastic bags, so if you really want to extend its shelf life, leave the produce in the open (tomatoes and bananas) or use ...

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

Image
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-César 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...

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 collec...

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

Image
... 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. Exercise 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 Col...