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Wednesday, September 22, 2010

On This Day in Science History - September 22 - Isotopes

September 22nd marks the passing of Frederick Soddy. Soddy was an English chemist who investigated the assortment of newly discovered elements that were decayed from radium, thorium and uranium. At this time, many of these elements had names like mesothorium, Radium A, B, C, D, E, F and Uranium X, each with a different half-life. Chemists were trying to separate elements like radiothorium from thorium but could not accomplish the task. Soddy theorized they were all the same elements and could not be separated chemically. They had slightly different atomic masses, but were the same elements. He gave the name 'isotope' to the atoms in this elemental mixture. He cited radium D and thorium C were actually two different isotopes of lead and acted the same as lead chemically.

He couldn't explain his theory with the current science. When the neutron was discovered by James Chadwick, Soddy's isotope theories suddenly made more sense. He also described the mechanics of radioactive decay. Alpha decay was the emission of a helium nucleus, 2 protons and 2 neutrons that lowered the atomic number by 2 and the mass by 4. Beta decay involved the emission of a beta particle (electron) that raised the atomic number by 1.
Soddy was awarded the 1921 Nobel Prize in Chemistry for this work and his theory. Find out what else occurred on this day in science history.

Can You Balance an Egg on the Equinox?

The autumnal equinox is Wednesday, September 22nd, 2010. This is the first day of fall in the northern hemisphere, or the first day of spring in the southern hemisphere. Are you familiar with the urban legend that it's easier to balance an egg on end on the equinox than on other days of the year? Test it and see! The autumnal equinox one of the two times during the year when the sun crosses the celestial equator and the spin axis of the Earth points 90 degrees away from the sun. Why should this affect your ability to balance an egg on end? The premise is that aligning the gravitational pull of the Sun with that from the center of the Earth should somehow make it easier to balance any object.

Test the Egg-Balancing Hypothesis Yourself

Take a carton of eggs and try balancing the eggs on end today. Can you stand any of them up (without resorting to tricks like putting salt under the eggs)? Can you stand eggs on their small ends as well as their large ends? Keep track of your results and repeat the process on the equinox. Do you note any differences? An easier hypothesis to test is: Eggs can only be balanced on-end on the equinox. If you can balance an egg today, you've disproven the hypothesis. It's that easy!

One thing I find neat about egg-balancing is that a balanced egg will hold its position until a vibration knocks it down. How long can you keep an egg standing?

Gemstone Color Chemistry

Gemstones are minerals that are considered pretty enough to use for jewelry and decorations. In many cases, the pure form of the mineral is clear (e.g., quartz), while impurities produce lovely colors, like the yellow and purple of the ametrine pictured here. In the case of ametrine, the quartz is discolored by iron. Are you interested in learning which transition metals are responsible for the color of your favorite gemstone?

Detergent and Bath Salts May Form Deadly Hydrogen Sulfide Gas

Mixing household chemicals, particularly cleaners, can produce toxic or even deadly fumes. You may be aware you should never mix bleach and ammonia or bleach and vinegar, yet might not realize trying to boost the cleaning power of detergent or toilet bowl cleaner is similarly dangerous. Sulfide salts or solutions react with acids to form hydrogen sulfide gas (H2S, shown). This is the chemical responsible for the rotten-egg smell, but exposure to hydrogen sulfide eventually deadens the sense of smell and can kill you. The gas is heavier than air, so it can settle toward the ground or find its way down stairs. If you smell the rotten egg odor when chemicals are mixed, it's a good idea to call 911 rather than just air out the room and return later because the gas could pose a threat to your family, pets and neighbors.

Mixing toilet bowl cleaner and bath salts or detergent and bath salts has been used as a suicide method in Japan and the UK. Readers should be aware this is a particularly selfish way to poison one's self, since the gas has the potential to harm rescue workers and innocent bystanders.

Tuesday, September 21, 2010

Nine new anthrax infections in Bangladesh

The number of anthrax infections continues to rise in Bangladesh, with nine new cases reported by officials with the Institute of Epidemiology, Disease Control and Research.

The latest cases, in the Pabna and Meherpur districts, bring the total number of anthrax infections since August 18 to 517 cases. No news of fresh infection of animals has been reported, however, an official with the livestock department told the nine new cases, seven were found in Gangni and one in Mujibnagar upazila in Meherpur and one in Shathia upazila in Pabna. The districts where the cases of infected people were found are Narayanganj, Pabna, Sirajganj, Meherpur, Kushtia, Tangail, Manikganj, Shatkhira, Lalmonirhat and Rajshahi.

Institute of Epidemiology, Disease Control and Research director Mahmudur Rahman told that vaccination of livestock is the main way to control anthrax.Bidhan Chandra Das, the assistant director of health and administration at the Department of Livestock, agreed, saying that his office was busy vaccinating animals in both the affected areas and in surrounding areas.“We are also distributing leaflets to make the people aware about anthrax,” Das told

The anthrax outbreak began on August 18 when villagers in the Sirajganj district in central Bangladesh became infected, reports. The cause was traced to anthrax-infected cows that were sold for meat to nearby villagers. All of the reported infections so far have been cutaneous and no deaths have been reported.
Anthrax is a potentially deadly, highly contagious disease. Cutaneous forms of anthrax are the most treatable, causing death in 20 percent of those infected. Inhalation anthrax, generally the result of a deliberate attempt to release anthrax spores, is far more deadly, causing death in 80 percent of those infected.

Anthrax infects 586 in Bangladesh

The total number of confirmed human anthrax infections in Bangladesh has reached 586 with three new cases detected in the last 48 hours.

The Institute of Epidemiology, Disease Control and Research, under the Ministry of Health and Family Welfare, told that one of the new caseswas detected by government health officers in Chuadanga. The remaining two cases were found at Bheramara upazila of Kushtia and Gangni upazila of Meherpur.
Cases of anthrax infection have been found in 12 districts since the disease first broke out in Sirajganj, IEDCR officials told

On This Day in Science History - September 21 - Bubble Chambers

September 21st is Donald Glaser's birthday. Glaser is an American physicist and neurobiologist who was awarded the 1960 Nobel Prize in Physics for the invention of the bubble chamber.

The bubble chamber is a detection device for particle physics that works on the same basic principle as the cloud chamber. A vessel is filled with a transparent liquid (usually liquid hydrogen) heated to just below its boiling point and aligned with a magnetic field. When the scientist is ready to take a reading, a piston is used to expand the chamber. This causes the liquid to become superheated. Any charged particles passing through the vessel will ionize the liquid and cause bubbles to appear along the particle's path. The bubble density and path shape can give information on the type, charge and lifetime of the particles.

Bubble chambers have been replaced by newer methods of detection in modern particle research laboratories, but they still have a place in demonstrations and education. The photographs taken of bubble trails bring the invisible world of particle physics to a light a student can see, measure and understand. Find out what else occurred on this day in science history.

Bangladesh says anthrax spreading in the country

DHAKA, Bangladesh – Bangladesh's government says anthrax has spread in the country, with some 585 people contracting the disease since late August.

The government's Institute of Epidemiology, Disease Control and Research released the figures Monday, reporting cases of anthrax in 12 of the country's 64 districts. So far, none of the victims have died and none are seriously ill.

While anthrax is not new to Bangladesh, there's no record of it spreading so widely.

The institute said that initially, 38 villagers were sickened by the bacterial disease in northern Sirajganj district after infected cows were slaughtered.

Humans typically get anthrax from touching infected animals or animal products. Human infections are potentially fatal.

Inkless Metal Pen Writes "Forever"

Back when I took nuclear physics, we had access to lead bricks used for shielding. We used the bricks for other than their intended purpose, such as building blocks, paper weights, and writing utensils. Lead makes a pretty respectable pencil, providing you don't mind the toxicity of the... well, lead. If you liked the look of lead with the inconvenience of the brick, Geekosystem reports on the release of an inkless pen that works on the same principle. The pen uses a metal alloy tip, which writes by leaving metal on the writing surface. The pen works upside-down and underwater and leaves an indelible mark. The pen (really more like a pencil) does contain lead and other metals kids shouldn't be eating, so it is recommended for adult use only. If you're interested, you can get your very own inkless metal pen from Vat19.

Difference Between Celsius and Centigrade

Depending on how old you are, you might read 38°C as 38 degrees Celsius or 38 degrees centigrade. Why are there two names for °C and what's the difference? Here's the answer:

Celsius and centrigrade are two names for essentially the same temperature scale (with slight differences). The centrigrade scale is divided into degrees based on dividing the temperature between which water freezes and boils into 100 equal gradients or degrees. The word centigrade comes from "centi-" for 100 and "grade" for gradients. The centigrade scale was introduced in 1744 and remained the primary scale of temperature until 1948. In 1948 the CGPM (Conference General des Poids et Measures) decided to standardize several units of measurement, including the temperature scale. Since the centigrade was in use in France and Spain as a unit of angular momentum and could refer to any scale divided into 100 parts, a new name was chosen for the temperature scale: Celsius.

The Celsius scale remains a centigrade scale in which there are 100 degrees from the freezing point (0°C) and boiling point (100°C) of water, though the size of the degree has been more precisely defined. A degree Celsius (or a Kelvin) is what you get when divide the thermodynamic range between absolute zero and the triple point of a specific type of water into 273.16 equal parts. There is a 0.01°C difference between the triple point of water and the freezing point of water at standard pressure.

How Fluoride Works

Fluoride is the fluorine ion added to toothpastes and dental rinses to help protect your teeth from cavities. While increasing the concentration of systemic fluoride (e.g., through fluoridating drinking water) has not been proven to reduce the incidence of tooth decay, direct contact between fluoride and teeth strengthens and helps remineralize damaged enamel. Here's how it works:

•The calcium and phosphate compound which makes up tooth enamel is a modified form of hydroxyapatite, which is susceptible to attack by acids. Bacteria that thrive on the sugars found in the mouth multiply on dental surfaces and produce acids.

•Mechanical brushing of teeth dislodges these bacteria and rinses them away, but doesn't do anything to address the ongoing damage to enamel from acid exposure. Fortunately saliva neutralizes these acids and teeth use compounds found in saliva to remineralize the enamel. So, as long as the rate of demineralization and the rate of remineralization remain in balance, teeth remain strong and healthy.

•When more minerals are lost from teeth than are replaced, dental caries or cavities form. Fluoride helps by interacting with hydroxyapatite to form a stronger compound that is less-susceptible to acid attack. Also, fluoride remineralizes damaged enamel (though it can't fix a cavity once one has formed). There is some evidence fluoride may inhibit the growth of bacteria on teeth or limit their capacity for producing acid.

•Even though you spit out toothpaste and probably rinse your mouth, enough fluoride remains on your teeth and in your saliva to confer protection for a while after brushing your teeth or using a fluoridated rinse.

নেপালের প্রধানমন্ত্রী খাদগা প্রসাদ শর্মাকে ফোন দিয়েছেন প্রধানমন্ত্রী শেখ হাসিনা

নেপালে বিমান বিধ্বস্ত হওয়ার ঘটনায় দেশটির প্রধানমন্ত্রী খাদগা প্রসাদ শর্মাকে ফোন দিয়েছেন প্রধানমন্ত্রী শেখ হাসিনা। নেপালের প্রধানমন্ত্রী গ...

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