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Showing posts from February 2, 2014

This Day in Science History - February 6 - Joseph Priestley

February 6 th marks the passing of Joseph Priestley. Priestley was an English theologian and natural philosopher who is best known with this experimental works with gases or "airs". He was the first to identify several gases including the element oxygen. This discovery helped answer the old question: Why do things burn? The prevailing theory of the time held there was a substance present in all things called phlogiston. Things would burn until they become saturated with phlogiston and any fire would go out. Priestley's found his new air greatly increased the process of burning and called it "dephlogisticated air" since it appeared to contain no phlogiston. Even though his discovery seemed to support the phlogiston theory, it was one of the key elements to launch Lavoisier's chemical reaction theories that started the Chemical revolution of the 19 th Century. Priestley began his work with gases with a ready supply of phlogistated air, or carb...

How To Calculate Atomic Mass

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One common chemistry homework assignment is finding atomic mass. The atomic mass is the sum of the masses of the protons, neutrons, and electrons in an atom, but the electrons have so much less mass than the protons and neutrons that they are left out of the calculations. Atomic mass thus becomes the sum of the mass of an atom's protons and neutrons. It's not difficult to find atomic mass, but there are three types of problems you may be asked to perform, depending how advanced your class is. Here's a look at how to find atomic mass, no matter how the problem is presented.

Make Your Own Yogurt

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Most chemistry projects are not edible. However, there is a great deal of chemistry in the food we eat. For example, beer, wine, cheese, and yogurt all require chemical reactions to turn one edible product into another. Making yogurt is a great project for all age groups, plus it's easy to work into lessons about proteins, pH, and fermentation. Even if you don't care about chemistry, it's worthwhile to learn to make your own yogurt. It's easy to do and results in a healthy, natural food that contains a lot of nutrients and probiotics

Ice on Fire Chemistry Demonstration

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Set real water ice on real fire by applying a simple chemical reaction. Okay, really the fire is burning between the ice cubes, but the effect makes it look like the ice itself is on fire... here's what to do.

Grow Glowing Crystals

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It's as easy to grow glowing crystals as it is normal crystals. You have a few options: Add glowing craft paint or glue to the crystal solution. The crystals may or may not incorporate the chemical into their matrix, but when you pull the crystals out of the solution, some of the glowing chemical will remain on the exterior, causing your crystals to glow. Make regular clear crystals appear to glow by growing them on a glowing base or substrate. For example, you can make a glowing crystal geode by painting the inside of an eggshell or plaster mold with glowing paint and growing clear or pale-colored crystals inside the glowing base. Make crystals that glow when exposed to black light by mixing yellow highlighter ink into the crystal growing solution. These crystals will glow under ultraviolet (black) light. Also, regular glowing crystals will glow more brightly under black light. Some natural crystals glow under ultraviolet light, without adding any chemicals.

Hemagglutinin and Food Poisoning from Beans

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Here's a fun fact: Eating soaked raw or undercooked beans can result in food poisoning. The culprit is a plant lectin known as phytohaemagglutinin or simply hemagglutinin, a chemical known to cause agglutination of mammalian red blood cells and to disrupt cellular metabolism. According to the US Food and Drug Administration, phytohaemagglutinin is found in many types of beans, but red kidney beans contain the highest levels of hemagglutinin. White kidney beans contain a third as much toxin while broad varieties of beans contain 10% as much hemagglutinin as red kidney beans. This is still plenty, since you only need to eat 4-5 undercooked red kidney beans to get sick. Bean Poisoning Symptoms Symptoms start to appear within 1 to 3 hours after consuming the beans and include nausea and vomiting followed by diarrhea and, in some cases, abdominal pain. Although the symptoms may be severe enough to warrant hospitalization, they resolve spontaneously within a few hours....

This Day in Science History - February 5 - Indiana Pi Law

On February 5, 1897, the Indiana General Assembly voted unanimously to pass a bill set the value of π equal to 3.2. The bill actually dealt with issues behind an old geometrical puzzle involving squaring a circle. Is it possible to create a square with the same area as a circle in finite steps using only a compass and straightedge. An Indiana amateur mathematician named Edwin Goodwin believed he had discovered the elusive solution to this problem. He approached his state representative, Taylor Record with an idea that would gain him recognition for his achievement, and help his home state out in the process. Record introduced bill.

Top 10 Tips To Pass a Chemistry Test

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How do you pass a chemistry test? Of course, the most important step is to study for the test! Yet, way you took the test. Chemistry tests usually a mixed bag of memorization, understanding the concepts, and working problems. It can greatly help your grade to go into the test with a test-taking strategy... Here's what you do you may have studied for a test, felt like you were going to ace it, and then gotten a big fat "F" on the returned exam. Okay, maybe it was just a "C" or a "D", but my point is: you didn't do as well as you thought you would. Do you know why? It likely had to do with the

This Day in Science History - February 4 - Friedrich Hund and Hund's Rule

February 4 th is Friedrich Hund's birthday. Hund was a German physicist who introduced a method to use molecular orbitals to determine electron structure of molecules and bonds. Hund's rules are a set of rules that determine the ground state of a multi-electron atom based on the energy levels of the filled orbitals. Hund proposed a set of three rules electrons follow to fill up "shells" or orbitals in multiple electron atoms. In chemistry, only one rule is generally referred to as "Hund's Rule". This rule comes in to play when determining the electron configuration of an atom and the Aufbau principle. Hund's rule deals with the quantum number dealing with spin, s . The s quantum number has two possible values, +½ and -½, also known as "spin up" and "spin down". The rule states that in an orbital, electrons will fill all available positions of the same value of s before the opposite spin value appears. Determining an...

Chelyabinsk Meteor Fragments Given to 2014 Sochi Gold Medalists

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Olympic athletes who win the gold at Sochi on February 15th are in for a special treat -- a medal containing meteorite pieces from the Chelyabinsk meteor, which streamed across the Russian sky on February 15, 2013. The meteor is believed to have been the largest natural object to enter the atmosphere and ultimately fragment and crash into the Earth as meteorites since the 1908 Tunguska event struck Siberia. Gold medal winners on February 15th will get the regular gold medals, plus the 10 athletes will be awarded special commemorative medals with a piece of meteorite embedded in their centers. The Chelyabinsk meteor produced chondrite meteorites that contain 10% iron. The medals holding the meteorite fragment have been crafted of gold and silver. Fifty of the medals have been made, with the other 40 going to private collections. According to Chelyabinsk Region Culture Minister Aleksey Betekhtin, " We will hand out our medals to all the athletes who will win gold on...

This Day in Science History - February 3 - Space Race Firsts

February 3 rd , 1966 was a day for two 'firsts' during the Space Race between the United States and Soviet Union. The United States launched the first meteorological satellite, the ESSA-1. ESSA-1 (Environmental Science Services Administration) would take photographs of cloud cover and transmit the data to the National Meteorological Center. It would be supplemented by 8 other ESSA satellites over the next three years and provided weather information to receiving stations in 45 different countries. The Soviet Union successfully landed a probe on the surface of the Moon for the first soft landing on another celestial body. The Luna 9 spacecraft touched down and began taking photographs of the area around the landing site. Luna 9 was the second spacecraft to reach the moon after the Luna 2 probe crashed into the surface in 1959.

How Hard Is it to Make Beer?

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Chemistry isn't just for the classroom. In everyday life, you encounter chemistry in cooking and cleaning... really, just about everywhere. Some hobbies use a lot of chemistry. For example, if you get into home brewing, you'll learn about how fermentation works, so you can control alcohol and sugar content of your beer. Is beer hard to make? Not at all. The trick is to make good beer.

What Do Whales Drink?

Have you ever wondered what whales drink? You probably know all animals require water to live. Humans drink fresh water and get water from the foods we eat. If we eat foods that contain enough water, we could get the water we need without actually drinking it. If we drink seawater the salt overwhelms our kidneys, essentially making us thirstier. However, whales ingest some seawater with the foods they eat, yet are fine. Just like us, whales need fresh water in order to live. They get most of this water from the food they eat (krill, fish, or plankton). Whale kidneys are made to extract water from their food and possibly some seawater. This is similar to the way terrestrial desert animals get water from their food.