Uniones químicas I - Química Antes de analizar los tipos de uniones químicas, en necesario entender algunas propiedades de los elementos, como la Electronegatividad. Ésta, se define como la capacidad relativa de un elemento, para atraer electrones en una unión, es decir, se define en una unión de elementos, quién atrae a quién. Los niveles de electronegatividad, se definen a partir, de la regla del octeto. Esta regla, tiene una relación directa, con la independencia de los gases inertes, respecto al resto de los elementos Analizado su CEE, notamos, que en todos, es nS2 NP6, significa así, que su último nivel de energía está completo, con 8 electrones totales, siendo esto, a lo que aspiran el resto de los elementos, para lo cual, tienden a combinarse. Las uniones químicas, se clasifican según la diferencia de electronegatividad, de los elementos que participen, en una unión. Cuando la diferencia es grande, se da una unión Iónica. Otro tipo de unión es la covalente, que se da entre elementos, de alta electronegatividad.
Something surprising happens to your body when you freedive Featured image: Photo of freediver Hanli Prinsloo by Annelie Pompe. In 1949, a stocky Italian air force lieutenant named Raimondo Bucher decided to try a potentially deadly stunt off the coast of Capri, Italy. Bucher would sail out to the center of the lake, take a breath and hold it, and free-dive down one hundred feet to the bottom. Waiting there would be a man in a diving suit. Scientists warned Bucher that, according to Boyle’s law, the dive would kill him. Boyle’s law, which science had taken as gospel for three centuries, appeared to fall apart underwater. Bucher’s dive resonated with a long line of experiments — most of them very cruel and even monstrous by modern standards — that seemed to indicate that water might have life-lengthening effect on humans and other animals. He started the experiment by leading volunteers into an enormous water tank and monitoring their heart rates as they dove down to the bottom of the tank. This discovery was as important as it was surprising.
The Mistaken Assumptions That Changed Physics History - The Nature of Reality “Don’t assume,” they always say. Last month, Avi Loeb, an astrophysicist at Harvard, published an essay on how mistaken assumptions have delayed the progress of astronomy. In the same spirit, I wanted to find out how the course of physics has been influenced by assumptions, acknowledged or otherwise. Can lessons from the past help us be more aware of the assumptions we bring to physics today? Is it desirable—or even possible—to work without assumptions? In the years after scientists came to accept light as a wave, brilliant researchers spent untold hours chasing after the “ether,” hypothetical stuff through which light waves were thought to propagate. If Einstein resolved one roadblock, he set up another. Dice or no dice? It’s hard to imagine an astronomer dismissing observational data on the evidence of her “instinct for astronomy,” which highlights a key difference between the two fields. Hidden assumptions can also live at the heart of how we do science.
The 2,400-year search for the atom - Theresa Doud Ernest Rutherford Although Ernest Rutherford is well known for his discovery of the nucleus, he did a lot of other research and experiments into topics other than the atom. He started his career studying electricity and magnetism and it wasn’t until he left his home of New Zealand and moved to Cambridge, England that he started working with the atom. Working under J.J. In 1911 after returning to England, Rutherford conducted his most famous experiment with alpha particles and gold foil which lead to his discovery of the nucleus. Where are the Electrons? After Rutherford discovered the nucleus, Neils Bohr (another of J.J. When Schrodinger’s equation is solved it does not give the exact location of an electron around a nucleus but as Max Born (yet another student of Thomson) discovered, it gives a probability density or area where the electron might be found. Schrodinger later went on to come up with a thought experiment or paradox that is referred to as Schrodinger’s Cat.
How do you know you exist? - James Zucker | TED-Ed René Descartes believed that most of what he acquired and learned came from the senses, but his senses had deceived him in the past. Can you give an example of when your senses have deceived you? Is there an experience that has made you doubt what you have seen or heard? Could this give you reason to doubt EVERYTHING you have learned from your senses? Descartes believed that if you doubt your own existence, you must exist to doubt it! René Descartes was an extremely talented man. Some famous quotes from Descartes are written below. “If you would be a real seeker after truth, it is necessary that at least once in your life you doubt, as far as possible, all things.” “Let whoever can do so deceive me, he will never bring it about that I am nothing, so long as I continue to think I am something."
How Does the Brain Learn Best? Smart Studying Strategies In his new book, “How We Learn: The Surprising Truth about When, Where, and Why It Happens,” author Benedict Carey informs us that “most of our instincts about learning are misplaced, incomplete, or flat wrong” and “rooted more in superstition than in science.” That’s a disconcerting message, and hard to believe at first. But it’s also unexpectedly liberating, because Carey further explains that many things we think of as detractors from learning — like forgetting, distractions, interruptions or sleeping rather than hitting the books — aren’t necessarily bad after all. Society has ingrained in us “a monkish conception of what learning is, of you sitting with your books in your cell,” Carey told MindShift. “How We Learn” presents a new view that takes some of the pressure off. Getting to Know Your Brain’s Memory Processes In an interview, he highlighted three take-home messages from his book: Forgetting isn’t always bad. The brain is a foraging learner. For example:
As Babies, We Knew Morality - Emily Esfahani Smith New research supports the understanding that all people are born with a sense of good and bad. What does that say about altruism, community, and the capacity to kill one another? Several years ago, an energetic young mother, Tia, was out and about with her infant Aimee when disaster struck: a group of men, accompanied by vicious dogs, surrounded the pair, snatched up Aimee, and brutalized Tia. They left her helpless and without her daughter. Aimee was eventually rescued. Mike, a squat and especially hairy fellow, didn't exactly look the part of a knight in shining armor. Is it correct to say that Mike's actions were "moral"? Though we share more than 95 percent of our DNA with these apes, many people think that morality is a uniquely human creation. Another idea, equally influential, is what the primatologist Frans de Waal calls veneer theory. But over the last decade, a growing body of evidence has challenged both the blank slate view of morality and veneer theory.
I Saw It on the Internet, part one This is part one of a series on posts on fact checking science related articles. Read part two of this series. -- Part 3 - Part 4 The next time you log into your favorite social media site, take a moment to look at all the “amazing”, “shocking”, and “astounding” articles that your friends and family have shared. You’ll learn that your food contains horrible poisons, that some household chemical is a cleaning marvel, or that Mars is going to look as big as the Moon on a certain day. Are those things true? They must be, because you saw it on the internet. Why fact check? Why should you verify information before posting it? Rest assured that if you don’t fact check the information, someone else will. Misinformation also hurts your “cause”. Why would someone post information that is wrong? Well, there are several reasons. Some articles are trying to convince you to accept their viewpoint, and are willing to “bend the truth” a bit in the process.
Brains flush toxic waste in sleep, including Alzheimer’s-linked protein, study of mice finds Scientists say this nightly self-clean by the brain provides a compelling biological reason for the restorative power of sleep. “Sleep puts the brain in another state where we clean out all the byproducts of activity during the daytime,” said study author and University of Rochester neurosurgeon Maiken Nedergaard. Those byproducts include beta-amyloid protein, clumps of which form plaques found in the brains of Alzheimer’s patients. Staying up all night could prevent the brain from getting rid of these toxins as efficiently, and explain why sleep deprivation has such strong and immediate consequences. Too little sleep causes mental fog, crankiness, and increased risks of migraine and seizure. Although as essential and universal to the animal kingdom as air and water, sleep is a riddle that has baffled scientists and philosophers for centuries. One line of thinking was that sleep helps animals to conserve energy by forcing a period of rest.
wait but why: Putting Time In Perspective Humans are good at a lot of things, but putting time in perspective is not one of them. It’s not our fault—the spans of time in human history, and even more so in natural history, are so vast compared to the span of our life and recent history that it’s almost impossible to get a handle on it. If the Earth formed at midnight and the present moment is the next midnight, 24 hours later, modern humans have been around since 11:59:59pm—1 second. And if human history itself spans 24 hours from one midnight to the next, 14 minutes represents the time since Christ. To try to grasp some perspective, I mapped out the history of time as a series of growing timelines—each timeline contains all the previous timelines (colors will help you see which timelines are which). A note on dates: When it comes to the far-back past, most of the dates we know are the subject of ongoing debate. For teachers and parents and people who hate cursing: here’s a clean, Rated G version.
The Story of Saliva Humans secrete two kinds of saliva, stimulated and unstimulated, no more alike than most siblings. The prettier child is stimulated saliva. It comes from the parotid glands, between cheek and ear. When a plate of Erika Silletti’s spaghetti carbonara makes your mouth water, that’s stimulated saliva. It makes up 70 to 90 percent of the two to three pints of saliva each of us generates daily. We’re going to gather some now. The Salivette instructions are printed in six languages. The Salivette makes an unmistakable point: your parotid glands don’t care what you chew. Allowing you to eat is the most obvious but far from the only favor granted by saliva. Vinegar, cola, citrus juice, wine, all are in the acid range of the pH scale: from around pH 2 to 3. Sugar contributes to tooth decay only indirectly. You may be wondering, though probably not, why newborns—who have no teeth to protect—produce excessive volumes of drool. About the Author Author photo by Chris Hardy Photography