字幕列表 影片播放 列印英文字幕 Smart Learning for All Why do mosquitoes bite only some people? Because they are lazy. No. There are a number of reasons why some people are more prone to mosquito bites. One of them is body odor. Millions of bacteria which live on our skin produce various gases. These gases form our body odor. Some of these body odors attract the mosquitoes. So, this is the reason why mosquitoes prefer me. Besides this, a popular research found that. Mosquitoes tend to bite people with Type O blood nearly twice as often as those with Type A. Exercising can also entice mosquitoes. This is because when we exercise, we release more carbon dioxide, heat, and sweat. Mosquitoes can detect this carbon dioxide and heat. They can also sense various substances in our sweat such as lactic acid. Thus making us more likely to get bitten. Why does hot air balloon float? Because it has invisible wings. No. It is because of density. Density is the measure of mass present per unit volume. Lesser the density, lighter will be the object. Now, density varies with temperature. It is so complicated. All right. I will explain. When a hot air balloon is on ground, the air inside and outside the balloon is of same temperature and density. However, when we turn on the burner of the balloon, the air inside the balloon starts getting hot. The molecules of air move faster and spread apart, taking up more space. Hence, the air inside the balloon becomes less dense than the air outside. As less dense air is lighter, the hot air balloon rises and thus, begins to float. What happens if a plane is struck by lightning? It will start glowing like a disco ball. No. Lightning is a massive flow of charge which carries thousands of volts of electric current. Thus, it is extremely fatal for living beings and can damage anything that comes in its way. Yes. It is really terrifying. Now many times, airplanes get caught in a heavy lightning storm. However, airplanes are designed to handle the lightning strikes. The outer skin of most planes is primarily made of aluminum. Aluminum is a good conductor of electricity. When lightning hits the airplane, the electric current travels through the outer skin of the plane. It does not pass into the plane. Eventually, it exits off through another extremity, such as tail. Thus, the airplane and the passengers within remain protected. Why can't we tickle ourselves? Because we are lazy. No. Areas that are more prone to getting tickled are our vulnerable areas like neck, stomach and armpits. Yes. You are right. Some researchers suggest that laughing on getting tickled by others could be a defense mechanism. It has evolved over the years when touched suddenly in vulnerable areas. This laughter could either be a way to laugh out of a tense situation. To show submission to the person tickling you to stop further tickles. Now, when we tickle ourselves. Our brain is programmed in such a way that it predicts and recognizes our own movements. It knows where our hands can reach. There is no element of surprise or threat, even if touched in vulnerable areas. Hence, we can't tickle ourselves. Why is fluoride added to water? To make water taste like soft drink. No. According to a prevailing study. When fluoride is added to public water supplies. At an average concentration of about 1 part per million or slightly below, it prevents tooth decay. But how? Enamel is the hard outer covering of our tooth. It is primarily made up of hydroxyapatite. Hydroxyapatite is a compound of calcium, phosphorus and hydroxide. Now, when bacteria in our mouth feed on food particles, they produce acid. This acid dissolves the hydroxyapatite leaving behind a residue of calcium and phosphate ions. This results in a tooth decay. Now, when we drink water containing fluoride. The fluoride binds with calcium and phosphate ions forming fluorapatite. As fluorapatite is less susceptible to acid attacks, it helps to stop the tooth decay process. For more educational videos please visit http://www.SmartLearningforAll.com Also, don't forget to subscribe to our YouTube channel.1 00:00:04,500 --> 00:00:06,000 Smart Learning for All Why do mosquitoes bite only some people? Because they are lazy. No. There are a number of reasons why some people are more prone to mosquito bites. One of them is body odor. Millions of bacteria which live on our skin produce various gases. These gases form our body odor. Some of these body odors attract the mosquitoes. So, this is the reason why mosquitoes prefer me. Besides this, a popular research found that. Mosquitoes tend to bite people with Type O blood nearly twice as often as those with Type A. Exercising can also entice mosquitoes. This is because when we exercise, we release more carbon dioxide, heat, and sweat. Mosquitoes can detect this carbon dioxide and heat. They can also sense various substances in our sweat such as lactic acid. Thus making us more likely to get bitten. Why does hot air balloon float? Because it has invisible wings. No. It is because of density. Density is the measure of mass present per unit volume. Lesser the density, lighter will be the object. Now, density varies with temperature. It is so complicated. All right. I will explain. When a hot air balloon is on ground, the air inside and outside the balloon is of same temperature and density. However, when we turn on the burner of the balloon, the air inside the balloon starts getting hot. The molecules of air move faster and spread apart, taking up more space. Hence, the air inside the balloon becomes less dense than the air outside. As less dense air is lighter, the hot air balloon rises and thus, begins to float. What happens if a plane is struck by lightning? It will start glowing like a disco ball. No. Lightning is a massive flow of charge which carries thousands of volts of electric current. Thus, it is extremely fatal for living beings and can damage anything that comes in its way. Yes. It is really terrifying. Now many times, airplanes get caught in a heavy lightning storm. However, airplanes are designed to handle the lightning strikes. The outer skin of most planes is primarily made of aluminum. Aluminum is a good conductor of electricity. When lightning hits the airplane, the electric current travels through the outer skin of the plane. It does not pass into the plane. Eventually, it exits off through another extremity, such as tail. Thus, the airplane and the passengers within remain protected. Why can't we tickle ourselves? Because we are lazy. No. Areas that are more prone to getting tickled are our vulnerable areas like neck, stomach and armpits. Yes. You are right. Some researchers suggest that laughing on getting tickled by others could be a defense mechanism. It has evolved over the years when touched suddenly in vulnerable areas. This laughter could either be a way to laugh out of a tense situation. To show submission to the person tickling you to stop further tickles. Now, when we tickle ourselves. Our brain is programmed in such a way that it predicts and recognizes our own movements. It knows where our hands can reach. There is no element of surprise or threat, even if touched in vulnerable areas. Hence, we can't tickle ourselves. Why is fluoride added to water? To make water taste like soft drink. No. According to a prevailing study. When fluoride is added to public water supplies. At an average concentration of about 1 part per million or slightly below, it prevents tooth decay. But how? Enamel is the hard outer covering of our tooth. It is primarily made up of hydroxyapatite. Hydroxyapatite is a compound of calcium, phosphorus and hydroxide. Now, when bacteria in our mouth feed on food particles, they produce acid. This acid dissolves the hydroxyapatite leaving behind a residue of calcium and phosphate ions. This results in a tooth decay. Now, when we drink water containing fluoride. The fluoride binds with calcium and phosphate ions forming fluorapatite. As fluorapatite is less susceptible to acid attacks, it helps to stop the tooth decay process. For more educational videos please visit http://www.SmartLearningforAll.com Also, don't forget to subscribe to our YouTube channel.
B2 中高級 美國腔 為什麼蚊子只叮咬一些人? 再加上4個視頻...#aumsum (Why do mosquitoes bite only some people? plus 4 more videos.. #aumsum) 20 3 AumSum 發佈於 2021 年 01 月 14 日 更多分享 分享 收藏 回報 影片單字