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- Welcome to Crash Course Organic Chemistry hosted by Deboki Chakravarti. We'll be tackling the notoriously complicated subject of organic chemistry, and hopefully having some fun along the way.
- A 20-part series examining the basics of important public health topics, created by APHA and Complexly Media
- The Anthropocene is the current geological age, in which human activity has profoundly shaped the planet and its biodiversity.
- An entertaining look at a collection of excessively hazardous chemicals know for their toxicity, explosiveness, corrosiveness, flammability and horrible smell. Their creators challenges in handling these chemicals and some of the historic incidents involving them are described.
- Scientists don't understand sex either. Because it's complicated. Your sexual determination, specified by you genes, doesn't always specify simply male or female but maybe something in between. And your sexual differentiation, which is how your genes are processed into your physical anatomy, doesn't always follow the 'textbook' process. Here's a bunch of ways human sexual development varies from person to person.
- Earth's Mantal is not the fluid uniform magma as most of us have been taught. It contains anomalies such as two content size protrusions under the Pacific and Atlantic Oceans. Geologist speculate they may result from water that has leaked from the oceans into the mantle forming iron peroxide. The protrusions seem to be associated with hot spots on the surface such as the Hawaiian volcanoes.
- Damascus steel was prized for it's ability to produce strong ultra sharp swords. But the recipe was lost in the 1800s. Now it is understood that the steel was produced as crucible steel which permits control of carbon content at lower temperatures though the process takes considerably more time. In addition the iron used to source the steel contained vanadium which is thought to catalyze the formation of iron carbide crystals and also appears to have caused the formation for carbon nanotubes within the steel.
- Tasmanian Tigers, also know as thylocines, were declared extinct in 1986 and there have been no confirmed sightings since around 1940. But that doesn't stop people form seeing them. People really want to find one. Perhaps that's because they were the largest marsupial carnivore to live alongside humans or perhaps because humans caused their demise by hunting them to protect live stock and by introducing competing animals such as dingoes.
- Astronomers generally considered details of the Milky Way's structure unique as the result of an early collision of two galaxies from a time when such collisions would have been rather rare. Think again. The first time an astronomer looked at anther galaxy of the MIly Way's type it found similar structures. In other news astronomers have found a spiral galaxy of record breaking age by looking in the public archives.
- You would think after living here for all of human civilization that geologists would know the Earth pretty well. But Earth is still dishing up strangeness. There are explosions, rumblings, craters, hills etc. that don't fit any of the established geological rules.
- Since they are rampant disease carriers there's been a good deal of research focused on what attracts mosquitoes to people. And there has been some success. Though not silver bullets Hank shares the research results and suggests a few things you can try.
- Baby volcanoes, a miniature mountain ranges and a tiny dessert aren't what they appear to be. A closer look or a broader view reveals aspects of these geological features that aren't so obvious. Volcano turns out to be a geyser or a vent from a gigantic volcano. The mountain range actually is a volcano. And the dessert is home to plants that don't mind a pile of wind blown sand.
- 1.1 billion years ago the super continent of Rodia was breaking up and North America started splitting in two. A mid ocean rift even formed between the eastern and western parts. Just then the separation stopped and the two parts merged together again.
- In 1998 Roy Baumeister published a definitive study showing that ego depletion (meaning will power is a limited resource) is real. But then in 2010 studies began finding the opposite and other labs were unable to reproduce Hagger's results. Controvery ensued and continued to this day (May 2016). But there are also concerns that the experimental methodologies used in the social science may be unreliable.
- It appears that epidemics date back to shortly after the dawn of civilization, perhaps six thousand year ago. Here are 6 epidemics from the past where it is unclear what caused them even though they killed tens of millions of people when human populations were much smaller than today.
- If you're an internet troll you probably know why you do it. If you're not you're probably asking 'why?'. Psychologists have wondered too and have taken an active interest in researching the subject. There seems to be a broad spectrum from people who take advantage of their online anonymity to joke around to people with deep seated psychological problems.
- There are some very good reasons for animals to be deceptive. Not getting eaten or your babies getting eaten is high on the list as is protecting your food supply from thieves. There there's sex. Every guy knows if you want to get the girl you have a better chance if you appear better than you really are. Here's how some animals do it.
- Game theory is a field of mathematics conceived by John Nash that deals with how people handle situations where they are effected by other people's decisions. Hank reviews what game theory has to say about competitive situations so an individual obtains their best result and cooperative situation so individuals obtain a fair result.
- Evolution has accomplished a lot but because it has no idea what's coming next it can't plan ahead. That sometimes results in some pretty cumbersome ways of surviving. But they work so we keep them. Here are five examples with scientists' best explanation of how they came about.
- 2012– 11mTV EpisodeIs it true that there is just a few percent of different between our DNA and chimpanzees? How can that little difference in our DNA make humans so different form chimpanzees? Or are we really all that different? And how do scientist know? And for that matter how do they figure it out?
- 2012– 28mTV EpisodeAren't plastics wonderful? Too bad they're such a problem. They cause pollution. Harm sea life. Maybe even harm us. So what can we do about them? Or are the alternatives even worse? The first step is to understand the problem from every perspective.
- Green diamonds are formed when they occur next to a radiation source such a uranium or thorium ore. The radiation for these elements is strong enough to knock a carbon atom out of the diamond's crystal lattice. If this happen enough the diamond appears green.
- Nobody wants to go to see a doctor. So it's tempting to treat yourself at home. There are plenty of home remedies for many medical conditions and more pop up on the Internet every day. The question is; Do they really work? Here are six the definitely don't.
- Everyone knows koalas are the cutest animal on the planet and love eucalyptus leaves. But eucalyptus is toxic and has very little nutritional value. How do they survive on that? Big surprise, they have a bunch of adaptations. So today, in 2021, now that the fires are out, their biggest challenge is an epidemic of chlamydia.
- 2012– 6mTV EpisodeCoulomb's law states that the force between two electrical changes varies with the square of their distances - exactly the square of their distances. Newton thought the same was true for the distance between two masses but it isn't. It took Einstein's theory of General Relativity to explain why. Which makes scientists wonder about Coulomb's Law. But so far the exponent has been measured to be exactly 2 to twenty significant digits.
- When DNA gets twisted into a knot it doesn't work. Fortunatly our cells have enzymes that fix the problem by cutting the DNA, straightening it out and splicing it back together. So knots can be very, very important. So important that mathematicians created the field of knot theory to try to get a handle on knots and make them simpler to understand. But to hear Hank tell it you may think they're making it more complicated.
- 2012– 4mTV EpisodeThe Kola Superdeep Bore Hole is the deepest hole drilled by humankind reaching a depth of 12 kilometers when work was stopped. There were some surprises. The crust is hotter than expected making drilling impossible as the rock behaved like plastic. But there is water probably squeezed out of the crystal structure of the rock due to high pressure. And there are microscopic fossils.
- 2012– 6mTV EpisodeIn the Tularosa Basin, New Mexico is a unique environment know as White Sands. The 'sand' is comprised of the rare chemical gypsum, calcium sulfate. It's rare because it's water soluble so it took 70 million years of specific geological events to create and preserve this desert. But life isn't easy in world of pure gypsum so the resident plants and animals needed some major adaptations.
- Nuclear power is an electrical energy generation option that does not produce greenhouse gases that warm the Earth. But a few nuclear reactors have experienced cooling failures that have resulted in catastrophic explosions. The proposed molten salt reactor design promises to prevent such explosions. And it can use an alternative fuel to uranium that proponents believe with produce less radioactive waste: thorium.
- The flu virus is constantly mutating. So every year vaccine producers strive to tailor that year's vaccine to the predominant emerging strains. But in 2020 far fewer people caught the flu due to the precautions against CoVid-19. That makes it harder to determine which strains will dominate in 2021. And few people will be resistant to flu because they didn't catch it in 2020.
- Many plants are polyploid compared to animals that are diploid. That is animals have one pair of each chromosome. But plants can have two pair, three pair or in the case of strawberries, four pair. Polyploidy can have some advantages such as better control of genetic disease and more opportunities for mutations to evolve more rapidly. But it does require a bigger nucleus and more nutrients that aren't used for metabolism.
- A vast multitude of invertebrate fossils lay buried in a region near Cincinnati Ohio called Caesar Creek and thousands of the fossils litter the surface. They formed when Ohio resided near the equator during the Ordovician Period when the region was covered by a shallow sea.
- Have you noticed those little strings when you look at a plain bright surface? Those are floaters; little fibers of collagen casting a shadow on your retina. And they will be there for the rest of your life. But not to worry. Everytime one stops moving around your brain will learn to ignore it and you won't see it any more.
- Before being distracted with founding a nation Benjamin Franklin spent a decade working at the forefront of the study of electricity. Among his scientific accomplishments are demonstrating that electricity is one force not two and that lightning is indeed electricity. Ever practical he used his work to invent the lightning rod.
- The hypnic jerk is a muscle contraction that may occur just as you're falling asleep. Often it causes you or your bed partner to wake up. Sleep experts speculate it may be a reaction to a feeling of falling as your brain shifts to sleep mode. Research shows it may be promoted by caffeine, stress or strenuous exercise.
- Chatter, chirp, tweet and tweedle sound like bird and rodent sounds. And maybe they are even when there made by cats, both wild and domestic. Researchers think it may be a cat trying to impersonate their prey so it won't flee at the predators approach.
- We all know rivers run down hill. But some have been found to turn around and run backwards. The phenomenon can be caused temporarily by especially large tides or by earthquakes. But how do you explain a stretch of the Mississippi being seen running backwards for a day or the mighty Amazon running east to west instead of west to east.
- Black holes are making news. Astonomers have finally measured the mass of dwarf galaxy Leo 1 and found it is inordinately large for a galaxy its size. And galaxy NGC 7727 sport two super-massive black holes. Ironically, each galaxy may help explain the strangeness of the other.
- The flavonoids in chocolate have been shown to decrease blood pressure a bit and improve blood flow to the brain. Now the bad news. It takes a lot of flavonoids to have an effect, you have to take them every day and the flavonoids that are beneficial aren't the good tasting ones.