Totally Wrong Facts Everyone Still Believes (Part 2)

0:00 Let's get right into it. Number seven, bulls seeing red. You've seen it in movies, the bull charging at that bright red cape. Everyone thinks the bull gets furious because it sees red. But here's the thing, bulls can't even see the color red. They have only two types of coloring cells in their eyes for blue and green. So that famous red cape just looks like a dull grayish yellow blob to them. The real reason they charge is the movement. Bulls get triggered by things moving erratically and unpredictably. You could wave a blue cape, a white sheet, or even your grandma's floral curtains. If you move it with enough flare, that bull is coming for you. Scientists actually tested this. They waved various colored objects at bulls. The bulls charged at anything that moved, no matter the color. But when those same objects were stationary, the

0:46 bulls couldn't care less. So why the red cape? It's mostly for the show and to hide blood stains during the bull fight. Smart for the spectacle, but it has nothing to do with the bull's color preferences. Number six, knuckle cracking arthritis scare. Your grandma probably warned you that cracking your knuckles would give you arthritis. Turns out that's not quite right. That satisfying pop isn't your bones grinding together. Your joints are filled with a special fluid called synenovial fluid. This fluid contains tiny gas bubbles, mostly nitrogen. When you pull or stretch your fingers, you create space in the joint. This makes the pressure drop and those gas bubbles burst like tiny underwater fireworks. That's the sound. Once you've cracked your knuckles, you usually have to wait about 20 to 30 minutes to do it again. The gas

1:31 needs time to redesolve into the fluid. It's like your knuckles have a built-in cool down timer. Scientists have looked into this for decades. One doctor, Donald, famously cracked the knuckles on only his left hand for 60 years. He never cracked the knuckles on his right hand. After 60 years, both hands were perfectly fine with no signs of arthritis. He even won an Ignobbel Prize for this dedicated piece of self-experimentation. Arthritis is usually caused by things like genetics, aging, or injuries, not by popping gas bubbles. So, that satisfying pop is generally harmless. Number five, baby bird touch taboo. There's a widely held belief that if you touch a baby bird, its mother will detect the human scent and abandon it. This is a myth that has probably saved many young birds from

2:17 well-intentioned but unnecessary human interference. However, it's not scientifically accurate. Most birds have a very poorly developed sense of smell. They rely primarily on sight and sound to recognize their young and their nests. A mother bird is heavily invested in her offspring. She spent considerable time and energy building a nest, incubating eggs, and feeding her chicks. She's not likely to abandon them simply because they've been touched by a human. Bird banders and researchers handle baby birds regularly for study, and the parents typically continue to care for them. What can cause a bird to abandon a nest is significant disturbance or a perceived threat from predators. If humans are constantly around the nest making a lot of noise, or if the nest is repeatedly disturbed, the parent birds

3:03 might decide the location is too dangerous. If you find a baby bird on the ground, it's important to first determine if it's a nestling or a fledgling. A fledgling is a young bird that has most of its feathers and is learning to fly. It's normal for them to be on the ground. A nestling is younger, often featherless or with downy fluff, and should be in the nest. If it's a nestling, and you can safely return it to its nest, that's usually the best course of action. Your scent won't be the problem. Number four, cold weather, cold catch. Your mom probably told you to wear a jacket when it's cold outside, or you'll catch a cold. It's a common belief that being exposed to cold weather can make you sick, but being cold itself doesn't cause a cold. Colds are caused by viruses, most commonly rhino viruses. You have to come into

3:48 contact with one of these viruses to get sick. So why do more people seem to get colds in the winter? One major reason is that when it's cold, people tend to spend more time indoors. We gather in closer proximity to each other in heated, often poorly ventilated spaces. This makes it easier for viruses to spread from person to person through coughs, sneezes, or contaminated surfaces. Some research also suggests that cold, dry air might affect our body's defenses. For example, the lining of your nose might be less effective at trapping viruses in colder, drier conditions. But the primary factor is still exposure to the virus. If you were isolated in a very cold environment without any viruses present, you wouldn't catch a cold. Scientists in Antarctica, for instance, often go months without colds until new people

4:34 arrive, bringing viruses with them. So, while bundling up in cold weather is good for staying warm and comfortable, it's not a direct shield against cold viruses. Number three, sunist season story. Everyone thinks summer happens when Earth gets closer to the sun. That's completely backwards. Earth is actually farthest from the sun during northern hemisphere summer. Everything you thought you knew is a lie. The real reason for seasons isn't about distance at all. It's all about Earth's permanent lean. Our planet is tilted at 23.5° and it stays that way while spinning around the sun. Like that friend who can't stand up straight in photos. This tilt means different parts of Earth get different amounts of sunlight throughout the year. When the northern hemisphere is tilted toward the sun, those sunbeams hit more directly.

5:20 That direct hit means more heat and longer days, giving us summer. Think of it like holding a flashlight straight at a wall versus at an angle. When it's straight on, you get a bright, concentrated circle of light. But tilt that flashlight and suddenly the same light spreads out over a bigger area, making it weaker. That's exactly what happens during winter. The sunlight hits us at an angle, spreading the warmth thin. Meanwhile, the southern hemisphere is tilted away, getting slanted, weak sunbeams. That gives them winter. This tilt is also why Australia is having beach weather, while North America is shoveling snow. When we're leaning away from the sun, they're leaning toward it. If Earth didn't have this tilt, we'd have the same weather all year round. No more seasons, no more winter wonderlands

6:05 or summer beach parties, just one endless season. Earth's orbit isn't even a perfect circle. It's slightly squished, like an oval. But this difference is so tiny, it barely affects our temperature at all. It's all about the lean, not the distance. Number two, dogs vision delusion. Many people think dogs see the world only in black and white like an old movie. But that's not true. Dogs do see colors, just not the same way humans do. Humans have three types of color detecting cells or cones in their eyes. Dogs only have two types of cones. This means their color vision is more limited. They can see blues and yellows quite well, but reds and greens tend to look like shades of brown or gray to them. So that bright red toy you throw for your dog might not stand out as vividly to them as it does to you. A

6:50 blue or yellow toy would be much more distinct. While their color vision is different, dogs have other visual advantages. They have more rods in their eyes, which are cells that help with vision in low light. This gives them better night vision than humans. They also have a reflective layer behind their retina called the tapidum lucidum. This layer bounces light back through the retina, further enhancing their night vision. It's also what causes their eyes to glow in the dark or in flash photos. And of course, their sense of smell is thousands of times more powerful than ours. So, they rely on a combination of senses to perceive the world. Number one, eight glasses water rule. You've probably heard it a thousand times. You need to drink eight glasses of water every day. This 8x8 rule is widely believed, but it's not a

7:36 strict medical guideline for everyone. The idea seems to have originated from a 1945 recommendation by the US Food and Nutrition Board. They stated that a suitable allowance of water for adults is 2.5 L daily. However, that same recommendation also noted that much of this intake is contained in prepared foods. Over time, the part about food got forgotten and the eight glasses advice took hold. In reality, how much water you need depends on many factors. These include your age, gender, activity level, overall health, and the climate you live in. If you're exercising heavily or in hot weather, you'll need more water. Also, you get a significant amount of water from the foods you eat. Fruits and vegetables, for example, have high water content. Beverages like milk,

8:23 juice, tea, and even coffee contribute to your total fluid intake, while caffeine has a mild diuretic effect. The water in caffeinated drinks still helps with hydration for most people. Your body is pretty good at signaling when you need water. It's called thirst. So, while staying hydrated is crucial, the rigid eight glasses a day rule is an oversimplification. That's all for today. I'll be making similar videos in the future. Subscribe to see them.