Ignorance of Science
Perhaps because I had always been interested in science, and was a researcher till recently, I find it astonishing that many apparently well educated people have a lot of misunderstanding about natural phenomena that have been more or less understood by science. Interestingly, some of these things are taught at school level, and some at college level. Somehow, they don't seem to realise that these facts that they studied are really related to the world around us.
I remember a classmate in M.Sc. whom I met again after about three years or so. Learning that I was doing research in atmospheric physics, he asked me a question about the atmosphere (something like why the sky is blue). I told him that he should know because we had studied this in our M.Sc. class. After listening to my answer, he gazed at the sky for a few seconds and said, "Oh, so all that is real?" I was shocked to say the least. Apparently, many students think that what is taught is just for the examination. I hope things have improved now.
I have had the experience several times, while speaking to school students, that they say that thunder and lightning are caused by two clouds colliding. Some of them have even told me that their teachers told them this. Of course, a couple of school teachers too have told me this. In these situations, I have asked them about their concept of a cloud, and also how they think that there can be two winds from opposite directions that cause the clouds to collide. These have generally led to doubts in their minds.
Now let me explain briefly, for those who do not know, what we believe causes lightning and thunder. There is a type of cloud that stretches from close to the ground up to what is called the tropopause of the atmosphere. (The tropopause is at a height of about 18 km at the tropics and comes down to about 6 km at the poles.) This type of cloud is called cumulonimbus by meteorologists and is popularly known as thunderstorm. Because of its nature, it has strong circulation inside and is therefore avoided even by large aircraft. Since temperature decreases as one goes up, ice crystals exist in these clouds above some height. Though the process is not exactly understood, these ice crystals help to generate electric charges inside the cloud. The top of the cloud is generally positively charged and the bottom negatively charged. As the charge builds up, the voltage increases and eventually it becomes possible for the charge to flow and neutralise. This can happen either from the bottom of the cloud to the ground, between charge centres within the cloud or, if two clouds happen to form close together, from one cloud to the other. This is just like an electric spark that forms when the positive and negative terminals of a battery accidentally get short-circuited or power lines sometimes come close together in strong winds. Thus, a lightning discharge is a huge electric spark and thunder is a huge crackle that is produced in an electric discharge. As electric current passes through air, it heats the air suddenly. This leads to the sudden expansion of the air, which creates a wave that we call thunder.
Recently, I met a well-educated elderly person, with degree in science, and employed in a senior position. He told me that he had always been wondering about how clouds can cause such a huge sound and recently found the explanation in a general knowledge book. He told me that the sound is caused when two clouds collide because there are millions of ice crystals in them. I told him what I know but I am not sure that he was convinced. But then he came out with an astonishing observation. He said that if we go to some height, there is no gravitation, and therefore we can float in the air! He had apparently seen visuals of skydiving and thought that the people were actually floating! Again, I tried to tell him that they were not floating but were actually falling. But again, I am not sure he believed me. He asked whether it is not true that there is no gravitation on the Moon. He had seen people leaping over long distances on the Moon in Apollo videos. I tried to tell him that the gravitational force on the Moon was one sixth that on the Earth, but again I doubt that he believed me.
It is unfortunate that our education system fails to convey scientific facts to the students. This makes people easy targets of charlatans who make a living out of cheating such gullible people.