Subtitles section Play video Print subtitles It's AumSum Time. Can you guess the title of my next video? Hurry up. Write your guess in the comments section below. What is the big bang theory? Many of us wonder how everything, that is humans, trees, planets, stars, galaxies, and even space and time came into existence. How did our universe originate? Now, there are several theories, beliefs and myths about the beginning of our universe. However, the most widely accepted explanation is the big bang theory. Which scientists use to describe the initial formation of our universe It states that our universe began from a very hot and compressed point, which is also known as a singularity. Based on estimations, it is said that approximately 13.7 or 13.8 billion years ago, the singularity violently exploded. This explosion is called the big bang. Scientists claim that from this explosion or big bang, space, time, energy, matter. Then, stars, galaxies, humans, etc., came into existence. Now, you must be wondering, what happened before the big bang at singularity? It is said that at singularity, laws of physics and time did not exist. If time did not exist, then there is no reference point to determine what happened before the big bang. How can we smell things? I don't have a nose. So, how will I know? At the back of our nose, there is a tissue called olfactory epithelium. It is covered with mucus. This tissue has specialized neurons called olfactory receptor neurons. There are about 40 million olfactory receptor neurons. These neurons are chemoreceptors, that is, neurons which detect chemicals. They have a cool name. Now, when any substance releases its smell or odor, the odor consists of chemicals. When we breathe in, these chemicals enter our nose. When they reach the olfactory epithelium, the chemicals get stuck in the mucus, causing them to activate the neurons. As a result. These activated neurons send signals through the olfactory tract to the brain, informing it about the smell. Topic: Convex mirror. Why is a convex mirror used as a rear-view mirror? What an amazing car. But your rear-view mirror is missing. Don't use a concave mirror. It will usually show you magnified images. Why don't you listen to me? See, I was correct. Now put a convex mirror and see the result. Look. The image is much smaller, right? Do you know what the difference between the 2 mirrors was? If we use a concave mirror for our car, we will not be able to see the vehicles behind us properly. This is because the concave mirror will magnify the object and we will see a very enlarged image. Thus, we require a mirror which gives us a wider view of the vehicles behind us. In this case, a convex mirror proves to be the right choice. This is because a convex mirror forms a highly-diminished image, thus making the traffic look much smaller. As a result, we can see a large number of vehicles in a very small mirror. Why does helium make you sound funny? Because helium converts you into a joker. No. Air mainly consists of gases such as nitrogen and oxygen. It is present in our surroundings, lungs, mouth, nose, etc. When we speak, air from our lungs passes through the vocal folds making them vibrate. These vibrations make the air in our mouth and nose to vibrate back and forth, producing sound. The speed of sound in air is about 340 meters per second. My running speed is 500 meters per second. Please listen. Helium is lighter than nitrogen and oxygen. Being lighter, sound travels faster in helium as compared to air. Hence, when we inhale helium and try to speak, the sound produced travels faster, thus producing that funny voice. Why do our teeth turn yellow? Because our teeth need some color in their lives. Our teeth basically consist of three parts. The outermost part is enamel. Enamel is white in color. Beneath the enamel, there is dentine. It is yellow in color. Then comes the part called pulp, which has blood vessels and nerves. Is this the same pulp found in our fruit juices? No. Please concentrate. When we drink or eat acidic fruits and beverages like lemon, orange juice, soft drinks, etc. They erode or wear away the enamel, exposing the yellow dentine and thus, making teeth appear yellow. However, did you know that some people's teeth are naturally yellowish? This is because in such people, the layer of enamel is thin causing the yellow color of the dentine to appear more clearly Thus, making their teeth appear naturally yellow.
B2 US mirror big bang olfactory convex enamel helium What is the Big Bang Theory? | #aumsum 29 2 AumSum posted on 2019/04/13 More Share Save Report Video vocabulary