 Have you guys ever seen those interviews with celebrities where they answer Google's most asked questions? Well, I figured why not do that, but with the most common science questions that people are asking. Besides answering what people are actually wondering, I figured it might help grow watch time, which is always nice. So let's jump in. First up, why is the sky blue? Well, not that I recommend it, but if you look straight up at the sun, it would actually look white or slightly orangeish-yellow. It's light that's making a straight path from the sun to your eyes. But if you look at the sky somewhere else, you can still see things. That's because when light hits that part of the sky, some of it bounces off and travels to your eye. Think of it like when you're standing in front of a wall. You can see the wall because the light hits it and comes back to your eyes. Now, imagine you're standing in front of a dark cave. You look out into the cave, and all you see is darkness. That's because there's nothing for the light to bounce off of, and if no light bounces back to your eyes, you can't see anything. So now, back to the sky. Because blue light has a shorter wavelength than red light, it runs into more oxygen molecules for a given path, and so it's reflected more. So when you look at the sky, a lot of short blue light is reflected, and not a lot of longer red light is. And so that leads to you seeing a blue sky. Next up, why do dogs eat grass? A lot of people think it's to induce vomiting if they have an upset stomach. Kind of like what all those action heroes do when they've been poisoned in movies, but there's not a lot of evidence to support this. First off, only about a quarter of dogs vomit after eating grass, and many dogs distant relatives like wolves and coyotes regularly dabble in plant eating. A good explanation of why dogs eat grass is for the same reason they eat your slipper when you leave it unattended. They just like to eat things. Next, why am I so tired? Well, you're probably not getting enough sleep. Most adults need between seven to nine hours of sleep a night. On top of that, being sedentary a lot can make you feel tired. So oddly enough, exercising regularly can make you feel less tired throughout the day. But obviously, if you have concerns about yourself, you should be asking a doctor, not Google. Next up, why do cats purr? We don't 100% know the answer to this one. Normally, cats only purr around their mothers and their kittens. So when they purr around humans, it might mean that they think of us sort of like an adopted family. There's also the possibility that at least some cats purr to elicit a response from their human companions, whether it's them wanting petting, food, or just attention. There's even some evidence to suggest that purr occurs at a frequency that can increase their bone density. So maybe that's why they're so good with falls. Why is my poop green? With all the information that Google collects these days, that's an odd thing to be telling them, but it's pretty straightforward. This just happens when food moves through your intestines too quickly. The green color comes from bile and isn't a concern if it happens once in a while. Just be sure to eat some fiber and maybe some of that yogurt Jamie Lee Curtis is always talking about. Let's switch things up. Who discovered electricity? Just Googling it will tell you Benjamin Franklin for his well-known experiment where he flew a kite in a thunderstorm, allowing him to collect ambient electrical charge in a jar. But this ignores a lot of people like Michael Faraday, who discovered that moving a magnet through a coil of wire produces a current and Luigi Galvani, who shocked dead frogs to watch them twitch. Despite it weird that sounds, this was important to realizing that the same electrical pulses seen in lightning govern how muscles move and contract. Who discovered penicillin? Alexander Fleming discovered penicillin, the first antibiotic, after he failed to clean his Petri dishes before leaving on vacation. When he came back, he found bacteria covering his Petri dishes, except around an area where a piece of mold was growing. Although, it would take the largely forgotten Howard Flory to figure out how to refine penicillin for to be used as an antibiotic, saving an estimated 200 million lives. Who discovered DNA? This one's a bit of a controversial one. DNA was first identified in 1806 by the Swiss chemist Johann Friedrich Meischer, not Watson and Crick, who also stole Rosalind Franklin's data in the first place. While he was trying to discover the key components of white blood cells, when he put the cells in acid, he noticed something separate out of the solution and he got it to dissolve again by adding a base. He named the mysterious substance nucleon, because he thought it came from the nucleus. Unbeknown to him, he had actually discovered DNA. I hope you enjoyed getting a little smarter with us. If there are any other questions you want answered, be sure to leave them in the comments down below. And if you like this style of video, be sure to let us know that too. Have a great day, and remember, there's always more to learn.