# Well-known obvious facts that a lot of people are ignorant of **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [April 28, 2016, 12:06am UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294 "2016-04-28T00:06:05Z")\ **Posts on this page:** 20\ **Page:** 3
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [April 28, 2016, 2:44pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/41 "2016-04-28T14:44:27Z")
> [@Common\_Tater](#): > > The same side of the moon (pretty much) faces the earth all the time. Until satellites and manned spacecraft orbited the moon, no human had ever seen the “Dark Side” of the moon. I once pointed this out to an otherwise very intelligent person and he just laughed and didn’t believe it. WTF? This might interest you: [Remarkable images of Moon passing in front of Earth - Miscellaneous and Personal Stuff I Must Share - Straight Dope Message Board](http://boards.straightdope.com/sdmb/showthread.php?t=785788) > [@silenus](#): > > Dr. Oz is an idiot. Agreed: [Dr. Oz Grilled In Congress, Admits Weight Loss Products He Touts Don't Pass 'Scientific Muster' | HuffPost Latest News](http://www.huffingtonpost.com/2014/06/17/dr-oz-congress_n_5504209.html) ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [April 28, 2016, 2:53pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/42 "2016-04-28T14:53:46Z")
Dr. Oz is irrelevant. The ingredients lists themselves say that there’s sand in there. It’s usually listed as “silicon dioxide (to ensure free flowing)”. ---
**Author:** ![Face\_Intentionally\_Left\_Blank](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/face_intentionally_left_blank/32/288_2.png) [@Face\_Intentionally\_Left\_Blank](https://boards.straightdope.com/u/Face_Intentionally_Left_Blank)\ **Post date:** [April 28, 2016, 2:55pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/43 "2016-04-28T14:55:49Z")
> [@grrr!](#): > > cold weather itself does not cause one to catch a cold. This drives me INSANE! “You got a cold, must be the change in the weather.” No, it’s a freakin’ VIRUS, so, P.S., stay home and don’t give it to everyone when you get it. ---
**Author:** ![silenus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/silenus/32/166_2.png) [@silenus](https://boards.straightdope.com/u/silenus)\ **Post date:** [April 28, 2016, 2:59pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/44 "2016-04-28T14:59:21Z")
> [@Chronos](#): > > Dr. Oz is irrelevant. The ingredients lists themselves say that there’s sand in there. It’s usually listed as “silicon dioxide (to ensure free flowing)”. “Sand” does not equal “silicon dioxide” any more than “char-broiling” equals “diamonds on my burger.” ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [April 28, 2016, 3:07pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/45 "2016-04-28T15:07:31Z")
> [@Lemur866](#): > > That jello is rendered animal collagen. Surprisingly many people have no idea what it is, it’s just “jello”. Hee hee hee - I remember the first time my spouse got a look at my from-scratch chicken stock, which uses a lot of bones (basically, scraps and leftovers). “What’s that stuff in the pot?” “It’s chicken jello” “You’re kidding.” “No… it’s basically chicken-flavored jello.” ---
**Author:** ![kayaker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kayaker/32/441_2.png) [@kayaker](https://boards.straightdope.com/u/kayaker)\ **Post date:** [April 28, 2016, 3:10pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/46 "2016-04-28T15:10:47Z")
> [@Chronos](#): > > Dr. Oz is irrelevant. The ingredients lists themselves say that there’s sand in there. It’s usually listed as “silicon dioxide (to ensure free flowing)”. IANAGeologist, but although silicon dioxide is a major constituent of sand, I do not believe the two terms are synonymous. And calling “Dr” Oz an idiot is an understatement. ---
**Author:** ![Nava](https://avatars.discourse-cdn.com/v4/letter/n/da6949/32.png) [@Nava](https://boards.straightdope.com/u/Nava)\ **Post date:** [April 28, 2016, 3:13pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/47 "2016-04-28T15:13:38Z")
> [@silenus](#): > > “Sand” does not equal “silicon dioxide” any more than “char-broiling” equals “diamonds on my burger.” Yeap, the desiccant is extremely different from sand. Flashes used to be made with magnesium powder; they weren’t made with aluminum powder because this would have been way too dangerous, too unstable. Solid aluminum that’s not powdered is perfectly stable, your windows won’t explode in a flash of light. Having the same elemental composition doesn’t mean two things are the same. ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [April 28, 2016, 3:14pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/48 "2016-04-28T15:14:24Z")
> [@Sir\_T-Cups](#): > > Ms. Cups’ car has this feature. Mine doesn’t. > > I think it’s about a 50/50 thing. You just must be really lucky. I recommend Vegas I think it’s far more than 50/50. I cannot remember any cars I’ve rented that don’t have this marking. It’s what I use to guide me when I pull up for that first fill-up. I’m sure there are models that don’t have it but, for me, the vast majority of cars from at least the last decade have it. My brother and his wife were both incredulous, but when they checked their respective cars (one an Altima, and I forget what she drives), they were there. ---
**Author:** ![Procrustus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/procrustus/32/2994_2.png) [@Procrustus](https://boards.straightdope.com/u/Procrustus)\ **Post date:** [April 28, 2016, 3:15pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/49 "2016-04-28T15:15:43Z")
> [@](#): > > Originally Posted by Gatopescado View Post > I’ve got a lot of cars, and am pretty sure none of them have this “feature”. I can tell you without reservation, that every rental car I’ve driven in the past 5 years or so had this feature. That’s about 15 cars a year. Plus the two we own. I suppose there may be newer cars that don’t have it, but I haven’t run into one yet. ---
**Author:** ![Lemur866](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lemur866/32/434_2.png) [@Lemur866](https://boards.straightdope.com/u/Lemur866)\ **Post date:** [April 28, 2016, 3:25pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/50 "2016-04-28T15:25:48Z")
> [@Scumpup](#): > > Jell-O brand gelatin is made from animal products. If by jello you are broadly referring to flavored gel desserts, you’d have to look at the box. [Products aimed at the vegan and kosher markets are made from other substances.](http://www.peta.org/living/food/gelatin-alternatives/) Sure, but vegan alternatives to gelatin like agar aren’t gelatin. That’s why they’re alternative to gelatin. ---
**Author:** ![Scumpup](https://avatars.discourse-cdn.com/v4/letter/s/ce73a5/32.png) [@Scumpup](https://boards.straightdope.com/u/Scumpup)\ **Post date:** [April 28, 2016, 3:36pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/51 "2016-04-28T15:36:19Z")
> [@Lemur866](#): > > Sure, but vegan alternatives to gelatin like agar aren’t gelatin. That’s why they’re alternative to gelatin. Right, but the post to which I was replying used the word “jello” not the trademarked name Jell-O. Jell-O is a specific brand. IME jello in common usage means any kind of fruity gel dessert. If he had said gelatin is an animal product, or Jell-O is an animal product, I’d have kept quiet. ---
**Author:** ![WildBlueYonder](https://avatars.discourse-cdn.com/v4/letter/w/ce7236/32.png) [@WildBlueYonder](https://boards.straightdope.com/u/WildBlueYonder)\ **Post date:** [April 28, 2016, 3:38pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/52 "2016-04-28T15:38:09Z")
If you put a un-nutered female cat outside for any length of time, she will return pregnant, no doubt about this. ---
**Author:** ![voltaire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voltaire/32/313_2.png) [@voltaire](https://boards.straightdope.com/u/voltaire)\ **Post date:** [April 28, 2016, 3:45pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/53 "2016-04-28T15:45:17Z")
> [@faithfool](#): > > As for mine, it’s how many cell phone users I meet who don’t realize that you should turn off your mobile data while on your wifi. No need to pay to double dip, says I, and it saves on your battery too. If you meant to say the opposite, you’d be correct. Every phone I’ve ever seen automatically turns off mobile data when wifi connects. It’s wifi that you should turn off when you won’t be around any viable/familiar/secure wifi sources. ---
**Author:** ![Shoeless](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/shoeless/32/7099_2.png) [@Shoeless](https://boards.straightdope.com/u/Shoeless)\ **Post date:** [April 28, 2016, 3:48pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/54 "2016-04-28T15:48:58Z")
> [@steronz](#): > > Huh? My phones have always defaulted to wifi when available. I know this because when my wifi is up but the internet goes down, my phone stubbornly refuses to use the (working) mobile connection unless I go in and explicitly turn off wife. All of my smartphones have been like this. I wish MY smartphone would let me explicitly turn off wife! Maybe I need to switch carriers. ---
**Author:** ![steronz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/steronz/32/11765_2.png) [@steronz](https://boards.straightdope.com/u/steronz)\ **Post date:** [April 28, 2016, 3:56pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/55 "2016-04-28T15:56:07Z")
You need to jailbreak first. I was hoping nobody would catch that. ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [April 28, 2016, 4:21pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/56 "2016-04-28T16:21:10Z")
> [@shantih](#): > > How old are your cars? It seems to be a standard feature on newer cars, or at least I’ve seen it on every car I’ve been in since I learned this. Old. Newest is a 97. > [@Nava](#): > > Sometimes it’s not an arrow, it’s a little picture of a pump. My car is a recent model and has the little pump. None have arrows, and the ones that have little pump pictures, the nozzle on the pump corresponds to the (correct, right) side the filler is on, _EXCEPT_ the Jeep, which comes as no surprise. 😛 The other Jeep has two gauges that measure the quantity of gas within plus or minus 40 percent accuracy, except for the one that doesn’t work at all. 😃 But that’s okay, because that tank leaks and I stopped using it till I get around to fixing it. But no arrows! ---
**Author:** ![silenus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/silenus/32/166_2.png) [@silenus](https://boards.straightdope.com/u/silenus)\ **Post date:** [April 28, 2016, 4:22pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/57 "2016-04-28T16:22:45Z")
> [@steronz](#): > > You need to jailbreak first. > > I was hoping nobody would catch that. Be careful. The penalty for breaking your contact can be quite severe. Half your stuff, usually. ---
**Author:** ![minor7flat5](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/minor7flat5/32/258_2.png) [@minor7flat5](https://boards.straightdope.com/u/minor7flat5)\ **Post date:** [April 28, 2016, 4:29pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/58 "2016-04-28T16:29:31Z")
Not obvious to me, but maybe obvious to others… I had always imagined that the mommy-baby system had common blood flowing freely between them through wide open pipes. This is not the case. Mommy’s blood and baby’s blood meet at the placenta and pass stuff between them without mixing, like prisoners passing notes through a chain link fence. ---
**Author:** ![MLS](https://avatars.discourse-cdn.com/v4/letter/m/919ad9/32.png) [@MLS](https://boards.straightdope.com/u/MLS)\ **Post date:** [April 28, 2016, 4:55pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/59 "2016-04-28T16:55:58Z")
Some fetal cells do get into the maternal blood stream, though. If the fetus is Rh positive and mother is Rh negative, her immune system starts to build up antibodies. In subsequent Rh+ pregnancies there can be consequences for the baby as a result. These days there is [Rhogam](http://www.rhogam.com/FAQs) to prevent this. Things like Trisomy 21 (Down Syndrome) can also be diagnosed via a maternal blood test. ---
**Author:** ![Moriarty](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/moriarty/32/49_2.png) [@Moriarty](https://boards.straightdope.com/u/Moriarty)\ **Post date:** [April 28, 2016, 5:17pm UTC](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294/60 "2016-04-28T17:17:04Z")
> [@MLS](#): > > Some fetal cells do get into the maternal blood stream, though. If the fetus is Rh positive and mother is Rh negative, her immune system starts to build up antibodies. In subsequent Rh+ pregnancies there can be consequences for the baby as a result. These days there is [Rhogam](http://www.rhogam.com/FAQs) to prevent this. > > Things like Trisomy 21 (Down Syndrome) can also be diagnosed via a maternal blood test. Fetal stem cells can also help [heal](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2633676/) the mother! [Previous page](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294.md?page=2) [Next page](https://boards.straightdope.com/t/well-known-obvious-facts-that-a-lot-of-people-are-ignorant-of/753294.md?page=4)