字幕列表 影片播放 列印英文字幕 It's AumSum Time Hi guys. Can you guess the title of my next video? Hurry up. Write your guess in the comments section below. Are wisdom teeth still useful? Obviously. Because wisdom teeth make us intelligent. No. There are 32 permanent teeth, out of which four wisdom teeth begin to grow a little late. Now, when our ancient ancestors used to eat plant material and raw meat. They required big strong jaws and wisdom teeth to chew their food. As they learned to cook food, they no longer required those big jaws. Hence, through evolution, the jaws started to get smaller and smaller. But the wisdom teeth did not disappear through evolution. They still exist. But since they appear a little late, the remaining teeth usually take up the available space in the small jaw. Leaving no room for the wisdom teeth. Hence. They begin to grow at odd angles and push other teeth causing pain, swelling, tooth decay and even infection. Hence, in such cases, wisdom teeth can prove to be harmful and not useful. Why are airplane windows oval? Because I told the airplane manufacturers to do so. Stop bluffing. When airplanes fly at higher altitudes. The air pressure inside the airplane is more than the air pressure outside. Hence, the cabin slightly expands, thus creating stress which flows through the cabin's material. Now, when the windows were square or rectangular. The stress caused tension to build up at the corners of square windows. This tension produced cracks in the cabin, thus leading to crashes. So sad. Hence, this design flaw was corrected by making windows oval. Oval windows provide a smoother path for stress to flow due to which tension is not produced. Hence, airplanes are safe. How do migratory birds find their way? With the help of GPS. No. Every year, many migratory birds fly thousands of kilometers to find food, to avoid extreme weather, etc. But researchers don't know how these birds find their way and travel to the same location year after year. However. An observation suggests that migratory birds can detect the earth's magnetic field lines. That appear to emerge from south pole and merge into north pole. When migratory birds have to travel from north to south or vice versa. They align themselves with the magnetic field lines and travel to their location. Along with this. Migratory birds may also find their way by creating a mental map of their route using mountains, rivers, etc. Besides this. It is also believed that migratory birds use the location of the sun and stars. To find their way and reach the same location. Topic: Taste Buds Why mint tastes cold? Maybe because it is manufactured in Antarctica. Not at all. Wait, I'll explain. Our tongue is actually a muscle which consists of many taste buds or receptors. Are they similar to my earbuds? No. When foods having flavors such as sweet, salty, sour, bitter or umami. Come in contact with these taste receptors and activate them. They send signals to the brain, telling us their taste. However, when we eat mint, it feels or tastes cold. This is because mint contains a compound called menthol. Menthol does not activate the taste receptors. But instead it activates the cold sensing receptors in our tongue. Hence, these receptors send messages to our brain signaling cold. As a result, the brain thinks that something cold is present in our mouth. Thus making mint taste cold. Why does salt make food taste better? Wait. I'll explain. Salt which is basically sodium chloride makes almost everything taste better. Whether it is French fries, certain fruits, curries or even cookies. We like at least a little salt in all these foods. According to researchers. We have evolved to like salt maybe because our bodies need salt for survival. What? Salt for survival. Indeed. Sodium present in salt, maintains our blood pressure, transmits nerve impulses, etc. Whereas, chloride is used to produce hydrochloric acid in our stomach. Hence, to obtain salt, we have gradually developed a taste for it. Thus, salt in food makes it appealing and tasty. In addition to this, it is found that salt suppresses bitterness better than sugar. Researchers aren't sure how. Some researchers suggest that salt neutralizes the bitter tongue receptors. While some suggest that on adding salt, the brain interprets the taste as less bitter.