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  • It's AumSum Time.

  • How do some insects walk on water?

  • They do not walk.

  • They catwalk.

  • No.

  • Water has an unusual property.

  • What is that?

  • Each water molecule is attracted by other molecules around it in all directions.

  • But since the molecules at the surface have no molecules above them.

  • They get attracted inward more strongly.

  • These inward forces of attraction create surface tension.

  • Thus, making the surface act like a stretched membrane.

  • Now, the weight of insects like water strider and fishing spider is very less.

  • So, the force that the insects legs exert on the stretched water surface is lesser.

  • Than the surface tension.

  • Also, as their legs are spread wide apart.

  • Their weight gets further distributed among all the legs.

  • Hence, the insects' legs do not sink.

  • And just create dimples on the stretched water membrane.

  • Helping it walk on water.

  • Nuclear fusion.

  • Why is nuclear fusion not used to generate electricity?

  • You really want to know the answer to this, right?

  • But wait.

  • Before answering the question, let us understand what is meant by nuclear fusion.

  • When two lighter nuclei combine to form a heavy nucleus.

  • A large amount of energy is released.

  • This process is called nuclear fusion.

  • Where does this nuclear fusion take place?

  • You think that it takes place in a laboratory?

  • No, you are absolutely wrong.

  • Nuclear fusion takes place in the sun.

  • The nuclei of two hydrogen atoms join together to form a heavy nucleus of helium.

  • With the release of a large amount of energy.

  • How do you think this energy reaches us?

  • No.

  • It does not reach us through power lines.

  • Wait, I will tell you.

  • The energy released after nuclear fusion reaches us in the form of sunlight.

  • Ultraviolet radiations, heat, etc.

  • Hey.

  • But we are already producing electricity with the help of nuclear fission.

  • So, why do we require nuclear fusion?

  • For this, you need to first understand difference between nuclear fusion and nuclear fission.

  • As we already know, nuclear fusion is the fusion of two lighter nuclei.

  • With the release of a large amount of energy.

  • The exact opposite process happens in nuclear fission.

  • Here, a heavier nucleus splits into two lighter nuclei, releasing a large amount of energy.

  • This process of fission is used in nuclear power plants.

  • Where a heavy nucleus of uranium is split into lighter nuclei.

  • The energy that is released in this is used to generate electricity.

  • However, there is a major disadvantage of nuclear fission.

  • Wondering what it is?

  • The major disadvantage is that uranium is a radioactive element.

  • When uranium undergoes fission, it generates radioactive waste along with energy.

  • This radioactive waste is very harmful for most lifeforms and the environment.

  • Hence, we need to find a clean and safe source of energy to generate electricity.

  • What source would that be?

  • Would it be nuclear fusion?

  • You are right.

  • Then why are we not harnessing the energy of nuclear fusion to produce electricity?

  • This is because, for nuclear fusion, two conditions are required.

  • They are high pressure and high temperature.

  • Only when these conditions are met, can the two nuclei travel at very high speeds.

  • Resulting in collision.

  • On earth, it is extremely difficult to create such high pressure and temperature.

  • Even if we are somehow able to create these conditions.

  • The question is how will we control them?

  • As there are many questions unanswered and unsolved.

  • We have not yet succeeded in using nuclear fusion in the production of electricity.

  • Heat.

  • Why is a laboratory thermometer not used to check body temperature?

  • You have got fever.

  • Why don't you check your body temperature using a thermometer?

  • No.

  • Please do not use a laboratory thermometer.

  • You will not be able to get the correct reading.

  • Why don't you try another one?

  • This is called a clinical thermometer.

  • A clinical thermometer is different from a laboratory thermometer.

  • Seems like you have made your choice.

  • A clinical thermometer has a kink.

  • When we check our body temperature, the kink present in it prevents the mercury.

  • From falling back down, thus helping the thermometer to hold the temperature recorded by it.

  • And giving us an accurate reading.

  • Now, in a laboratory thermometer, this kink is absent.

  • This is because a laboratory thermometer is meant to measures immediate temperature.

  • Hence, after recording our body temperature, until we check it, the mercury will fall.

  • Thus, not giving us an accurate reading.

  • Ultrasound.

  • Why is ultrasound used in sonar?

  • Hey.

  • Looks like you are searching for a treasure hidden in a sunken ship.

  • Why don't you use a sonar?

  • It will emit ultrasounds and help you locate the ship.

  • You know what, I have a better idea.

  • No.

  • A music system will make ordinary sound.

  • So, it is of no use.

  • Do not fool me.

  • I know that the music system is the right choice.

  • See, you are not able to find the ship.

  • Now, will you use a sonar?

  • Look, you easily found the ship.

  • Do you know how a sonar could locate the sunken ship?

  • It was because of ultrasound.

  • Ultrasounds are sounds having very high frequencies which start from 20,000 Hertz.

  • So, is ultrasound used in sonar because of its high frequency?

  • You are absolutely correct.

  • Due to its high frequency, an ultrasound can penetrate to a greater depth.

  • Thus, helping us to locate the depth of the sea, sunken ships, etc.

  • But, I am not able to hear the ultrasound?

  • It is because human beings can hear sound frequencies from 20 Hertz to 20,000 Hertz.

  • As ultrasounds have frequencies higher than 20,000 Hertz, we cannot hear them.

  • Bad conductors of heat.

  • Why are two thin blankets warmer than one thick blanket?

  • Because two chocolates are better than one.

  • No.

  • To understand this, we need to first learn about bad conductors of heat.

  • Bad conductors of heat are the materials which do not allow heat.

  • To easily flow through them.

  • Air, wood and glass are some examples of bad conductors of heat.

  • In these examples, is our train conductor included as well?

  • Just listen.

  • A thick blanket allows much of our body heat to escape into the atmosphere.

  • However, when we use two blankets one on top of the other.

  • Air gets trapped between them.

  • This air being a bad conductor of heat, does not allow our body heat.

  • To easily flow into the atmosphere, thus keeping us warm.

  • Pathogens.

  • Why do we get fever?

  • So that we can take a holiday from work.

  • No.

  • Fever is a protective response of our body to fight against pathogens.

  • Such as bacteria, viruses and fungi.

  • These pathogens cause diseases.

  • Hence, when pathogens enter our body, the immune cells such as white blood cells.

  • Produce chemicals called pyrogens which are released into the bloodstream.

  • I thought like movies, they are released in theaters.

  • Please, pay attention.

  • Hypothalamus, which is a small part of our brain, regulates our body temperature.

  • However, when these pyrogens reach the hypothalamus, it starts to raise our body temperature.

  • Thus, producing fever.

  • Now, one of the reasons for producing this fever is that many pathogens.

  • Cannot survive at high temperatures.

  • Thus, they die and we remain safe.

  • Human tears.

  • Why do onions make you cry?

  • Because they cannot crack a joke.

  • No.

  • Onions consist of amino acid sulfoxides.

  • When we cut an onion, millions of onions cells rupture.

  • Releasing the amino acid sulfoxides along with some special enzymes.

  • These special enzymes react with amino acid sulfoxides.

  • To form a chemical called Syn-propanethial-S-oxide.

  • This chemical is volatile, that is, it easily evaporates at normal temperature.

  • Forming a gas.

  • When this gas reaches our eyes, it reacts with substance that keeps eyes lubricated.

  • And forms mild sulfuric acid.

  • What?

  • An acid in my eyes.

  • Absolutely.

  • This sulfuric acid gives us a burning sensation.

  • Now, in order to wash off this acid, our lacrimal glands produce a disinfecting liquid.

  • But when our eyes cannot hold any extra amount of disinfecting liquid.

  • It starts to fall down, making us cry.

  • Joints.

  • Why do knuckles pop?

  • So that when we get bored we can pop them for time pass.

  • No.

  • A knuckle is a joint in the finger where two bones come together or connect.

  • This joint is filled with a fluid called synovial fluid.

  • Synovial fluid is a viscous fluid containing dissolved gases like oxygen and carbon dioxide.

  • When bones move, the synovial fluid prevents them from grinding against each other.

  • It is so amazing.

  • Indeed.

  • When we stretch or bend our finger, the space between the two bones increases.

  • This causes the synovial fluid to stretch, thus creating low pressure in it.

  • Now, as gases are less soluble at low pressure.

  • The dissolved gases in the synovial fluid undissolve.

  • Resulting in the formation of a bubble, which we hear as the pop sound.

  • Why do animals' eyes glow in the dark?

  • Because they have hidden torches.

  • No.

  • Wait, I will explain.

  • Our eyes have a layer called retina which is made up of photoreceptors.

  • When light enters our eyes, it hits the photoreceptors.

  • Photoreceptors detect light, thus making it possible to see.

  • However, the light which does not hit the photoreceptors remains undetected.

  • Poor undetected light.

  • Now, nocturnal animals like owls, need to see better during the night.

  • Hence, their eyes have another layer below the retina called tapetum lucidum.

  • Now, when light does not hit the photoreceptors, it reaches the tapetum lucidum.

  • This layer acts like a mirror.

  • It reflects light back onto the photoreceptors.

  • Thus, giving them a second chance to detect light.

  • Some of this reflected light also comes out of the animal's eyes.

  • Thus, making it seem that its eyes are glowing.

  • 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 outer skin of the plane.

  • It does not pass into the airplane.

  • Eventually, it exits off through another extremity, such as tail.

  • Thus, the airplane and the passengers within remain protected.

  • Why cannot dogs eat chocolates?

  • Because I would love to have all the chocolates for myself.

  • Alright.

  • Now listen.

  • Chocolates and other cocoa products contain a toxic component called theobromine.

  • The darker the chocolate, the more theobromine and the more it is harmful.

  • But I eat chocolates and I am completely fine.

  • Our body quickly metabolizes the theobromine.

  • Thus, it is not quite harmful for us.

  • However, dogs process theobromine much more slowly.

  • So, it stays in their bodies for a longer time, resulting in vomiting, diarrhea, etc.

  • Moreover, if large quantities of chocolate are ingested by the dog.

  • Then the effects can be much more severe.

  • The heart rate of dog might beat twice its normal rate, increasing the blood flow.

  • This can prove to be lethal to the dog.

  • What is sleep paralysis?

  • No idea.

  • Sleep paralysis is a condition in which we are conscious.

  • But temporarily unable to move or speak.

  • It can usually occur when we suddenly wake up during REM sleep.

  • What is REM sleep?

  • Basically, there are four stages of sleep.

  • One of them is Rapid eye movement sleep, that is, REM sleep.

  • In this stage, we dream.

  • Researchers suggest that when we enter REM sleep, two chemicals, glycine and GABA.

  • Switch off the activity of cells in the brain that allow our muscles to move.

  • No.

  • This is so bad.

  • No.

  • It is actually beneficial because paralyzed muscles.

  • Prevent us from enacting our dreams in reality and getting hurt.