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  • It's AumSum Time

  • Hi guys.

  • Can you guess the title of my next video?

  • Oh.

  • Dance party.

  • Hurry up.

  • Write your guess in the comments section below.

  • Something's missing.

  • Sugar?

  • Salt?

  • No.

  • It's saliva.

  • To taste food,

  • The taste buds on our tongue need a liquid medium like saliva to bind food molecules to its receptors.

  • Saliva also contains an enzyme called amylase which breaks carbohydrates into simple sugars.

  • So, without saliva, foods having carbohydrates may taste different.

  • Also, saliva contains natural disinfectants which help wipe away harmful pathogens.

  • Topic: Sound.

  • Why do we hear echoes?

  • Hey.

  • Hold On.

  • Don't go into that room.

  • You don't want to listen to me.

  • Okay.

  • Then go ahead.

  • See, I warned you.

  • Will you listen to me now?

  • Don't worry.

  • The sound you heard was just an echo of your voice.

  • Let me explain what an echo is.

  • When we speak or laugh in a big empty hall, we hear our own sound repeatedly.

  • This is because our sound waves get reflected from the walls of the hall back to us.

  • The reflected sound that we hear is called an echo.

  • Hence, an echo is defined as the repetition of sound caused by the reflection of sound waves.

  • From a hard surface back to the listener.

  • Hey.

  • What are you doing?

  • Are you trying to hear an echo?

  • It is not that easy.

  • There are 2 ideal conditions for an echo to be heard.

  • When we speak or laugh, we hear our original sound at that moment.

  • The sensation of this original sound remains in our brain till 0.1 seconds.

  • This time is called the persistence of hearing.

  • When we utter sounds, some of our sound waves get reflected while some get absorbed.

  • If the reflected sound waves reach our ears before the completion of 0.1 seconds.

  • Then our brain does not perceive the original and reflected sounds as separate sounds.

  • They are interpreted as one sound.

  • Therefore, in order to hear two distinct sounds or an echo.

  • The time gap between the original sound.

  • The reflected sound or echo should be at least 0.1 seconds.

  • This is the first condition for an echo to be heard.

  • Do you know when the time gap will be more than 0.1 seconds?

  • This gets us to the second condition for an echo.

  • The minimum distance between the speaker and the reflecting surface should be at least 17.2 meters.

  • When the distance is 17.2 meters and we start speaking.

  • Assume that the original sound reaches our ears at this time.

  • The reflected sound reaches our ears at this time. , then the time interval between the reflected sound.

  • The original sound will be equal to 0.1 seconds.

  • As a result, we will be able to hear an echo.

  • Alright.

  • Now, let us try and hear an echo in this room?

  • It is even bigger than the previous room.

  • Now, why can't we hear an echo?

  • This is because there are many soft furnishings like sofas, carpets, curtains, etc., in this room.

  • They absorb most of the sound waves.

  • As the sound waves do not get reflected, we are not able to hear an echo in this room.

  • Hence, one more thing to consider.

  • If we want to hear an echo, is that there should be minimal use of such sound absorbing materials.

  • Topic: Distillation.

  • Is distilled water safe to drink?

  • How would I know?

  • Am I a detective?

  • Alright, alright.

  • I'll answer it.

  • Distilled water is obtained from distillation.

  • In distillation, the impure water is first heated, thus converting water to vapor.

  • Then, this vapor is condensed by cooling, hence converting vapor back to liquid water.

  • By this process, the impurities remain behind, giving us pure distilled water.

  • Now, even though distilled water is pure.

  • Some doctors say that we should not drink it for a prolonged period of time.

  • So, can I take a bath with it?

  • I haven't bathed since last Sunday.

  • Oh gross.

  • You are just impossible.

  • It is generally recommended to avoid drinking distilled water for a long period.

  • Because along with the impurities.

  • The minerals required for the proper growth of our body are left behind during distillation.

  • What is asthma?

  • It is a nickname for cinema.

  • Stop bluffing.

  • Asthma is a lung disease.

  • A person with asthma has red and swollen bronchial tubes with a lot of mucus.

  • As a result, the bronchial tubes get narrower than normal, thus making it hard to breathe.

  • Besides this, the bronchial tubes are highly sensitive to irritants like pollen, tobacco smoke, dust, etc.

  • When an asthmatic person inhales an irritant.

  • The tubes become much more swollen and more mucus is produced.

  • This causes further narrowing of the tubes.

  • This narrowing makes exhalation harder than inhalation.

  • Hence, carbon dioxide rich air gets trapped in the person's body.

  • He does not get sufficient supply of fresh oxygen.

  • As a result, the person can have severe shortness of breath and a feeling of tightness in the chest.

  • When an asthmatic person experiences such problems, he is said to have an asthma attack.

  • What are those 'do not eat' packets?

  • It is a top secret.

  • No.

  • It's not.

  • Do not eat packets usually contain silica gel which is a form of silicon dioxide.

  • Silica gel packets or do not eat packets are commonly found in products like packaged foods.

  • Leather articles, etc. because these products get spoiled by moisture.

  • Silica gel helps to keep them safe by adsorbing the moisture.

  • You mean absorbing the moisture, right?

  • No.

  • Absorption is a process in which a substance is taken into another substance.

  • Whereas,

  • Adsorption is a process in which a substance attracts and holds another substance on its surface.

  • Now, silica gel contains millions of microscopic pores.

  • If there is any moisture present around the leather articles or packaged foods.

  • Then the pores of silica gel attract the moisture and hold it on their surface.

  • Preventing the products from getting spoilt.

It's AumSum Time

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沒有唾液也能品嚐到食物嗎?| 舌尖上的中國#aumsum (Can we Taste Food without Saliva? | #aumsum)

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    AumSum 發佈於 2021 年 01 月 14 日
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