字幕列表 影片播放 列印英文字幕 I'm holding in my hands one of the most magnificent powerful marvelous chemicals in all of the universe and wondering if you would be okay with me if I had some Mmmm... It tastes so good Intro music This, my friends, is your run-of-the-mill table sugar It's made out of some sugar beets... Or... from a... sugar cane... There's no way to tell which But henceforth we're going to be... uhh... calling it by it's proper name which is sucrose. There's a bunch of different kinds of sugars but they're all sweet tasting, edible, carbohydrates So, carbohydrates... probably the tastiest word in the English language and aside from filling up your snack hole and making your kids get all spazzy sugar is one of the most important chemicals on the planet They're pretty much the primary source of energy for every thing on Earth Not this stuff exactly, this stuff is more of the Ahh... primary source of all cavities on Earth At the cellular level, pretty much every living thing on Earth, when it needs an energy fix whether it's a plant, an animal or a bacteria the first they turn to is sugar. Now where does sugar come from? Our earliest word is the energy used to create sugar come from, that of course is our friend the sun. These lovely sweet compounds are found in every single plant though in vastly varying quantities of course because it is the primary product of photosynthesis Now when we talk at all about photosynthesis on the biology crash course channel and when we do that episode - when we post it online you will see the link down in the description if you want to learn more about photosynthesis but for now let's just say that the importance of plants turning carbon dioxide and water and sunlight into sugar cannot be overstated Basically, plants use energy from the sun to split the molecules of water and the hydrogen from that water is combined with the carbon dioxide to create glucose So in effect, this whole process captures the energy of the sun and stores it as chemical energy in sugar I'm eating the sun I'm eating the sun right now It's under my tongue Problem That was a lot of sugar Now I'm worried I gonna have a stomach ache In addition to glucose and other common plant sugars, fructose, which has the same chemical formula it's just... rearranged a little bit... And even though they're very similar and contain the same amount of energy fructose actually tastes significantly sweeter which is why we like to put high fructose corn syrup into beverages That's why we get a wide range of tastiness in plants from super sweet potatoes to "not-sweet-at-all" potatoes which is why what we generally call starch - which is a complex carbohydrate is actually a bunch of sugar molecules all linked together All the way to the sugar in sugarcane is our old friend sucrose which was actually just a molecule of glucose and a molecule of fructose linked together Point is that all these sugars are important The reason why we think they're so delicious is because we need energy to survive and sugar is a really great place to get energy from And if it seems to you like I've been eating a lot of sugar in this video Keep in mind that I've maybe had about two... two, three teaspoons so far? The average American has about twenty-two per day so I've got a long way to go Twenty-two teaspoons a day, people That cannot be healthy I did a little bit of research and I discovered last night that just from drinking soda the average American drinks about fifty pounds of sugar a year We Americans generally have a heck of a lot more sugar than we need to have We should probably having more like six to nine teaspoons a day so you might want to rethink that all Captain Crunch diet you're currently on I'm not really designed for a world where sugar is infinitely available It's certainly pretty hard to come by something really sweet in nature and even if you find something - like a bunch of apples it's hard to eat a lot of apples without making yourself pretty sick Nowadays we've gotten around that by producing this wonderful white powder as well as the high fructose corn syrup that they put in absolutely everything these days So if you want my health advice... try and maybe eat the way that your caveman ancestors did fruits and vegetables maybe some complex carbohydrates here and there And I would suggest overall to not consume sugar in this manner Thank you for watching this episode of SciShow If you wanna learn more about sugar, check the links in the description You can also ask us questions, which we'll be happy to answer and suggest other topics for SciSchow in the YouTube comments. Hook up with us on Facebook and Twitter as well. Goodbye End credits music