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Showing posts from January 14, 2014

This Day in Science History - January 14 - Cato Guldberg

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January 14 th marks the passing of Cato Guldberg. Cato and Peter Waage were Norwegian chemists who discovered the chemistry law of mass action. The law of mass action relates the rate of a reaction to the concentration of the reactants. They had an interesting journey to get their work recognized and is a lesson in getting published in the 'right' scientific journals. They initially published their findings in a Norwegian scientific journal and consequently, gained very little recognition for their research. They republished their work in a French journal which did not attract any more attention. Their work remained obscure until German chemist, Wilhelm Ostwald published an article that mentioned the law and proved their results with experiments of his own. Dutch chemist Jacobus van't Hoff derived his kinetics equations in 1888 and received credit for the discovery, they republished again in a German journal and finally got the recognition for their work. 20...

10 Common Naturally Radioactive Foods

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Technically, all food is slightly radioactiv e. This is because all food and other organic molecules contain carbon, which naturally exists as a mixture of isotopes, including radioactive carbon-14. That's the basis for carbon dating , used to identify the age of fossils. However, some foods emit much more radiation than others. Here's a look at 10 naturally radioactive foods and how much radiation you get from them. 1. Brazil Nuts If there was an award for "Most Radioactive Food," it would go to Brazil nuts. Brazil nuts contain high levels of two radioactive elements: radium and potassium. Potassium is good for you, used in many biochemical reactions, and one of the reasons why the human body is itself slightly radioactive. Radium occurs in the ground where the trees grow and is absorbed by the plant's root system. Brazil nuts emit over  6,600 pCi/kg of radiation. Most of that radiation passes harmlessly through the body, plus the high levels...

10 Radioactive Foods

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Some of the foods you eat are naturally radioactive. Sometimes the radiation comes from isotopes that a plant absorbs as it's growing, while other foods are radioactive because they contain high levels of elements that exist as a mixture of isotopes. Pictured here is a common food that emits radiation.   Question: What Is Radioactivity? What is Radiation?    Unstable atomic nuclei will spontaneously decompose to form nuclei with a higher stability. The decomposition process is called radioactivity. The energy and particles which are released during the decomposition process are called radiation. When unstable nuclei decompose in nature, the process is referred to as natural radioactivity. When the unstable nuclei are prepared in the laboratory, the decomposition is called induced radioactivity. Answer: There are three major types of natural radioactivity: Alpha Radiation Alpha radiation consists of a stream of positively charged particles, called a...

How To Calculate Standard Deviation

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One of the most common calculations you'll be expected to perform on data is standard deviation. It is so important that most calculators have a button for it! However, you should be able to do this calculation by hand, plus you need to know which standard deviation formula to apply. That's right! There is more than one. Apply the population standard deviation formula when you are analyzing a complete set of data. This may be data from all the members of a class or all the trials of an experiment. Apply the sample standard deviation formula when you are analyzing a sample or set of samples from a larger population. Note that the sample standard deviation formula contains a correction factor, called Bessel's correction, that expresses increased uncertainty in how reliable your data is. Why would you do this? The correction factor helps form a more realistic prediction of what you could expect from future testing. It is helpful when you can't get data from ...