It's AumSum Time.
Can you guess the title of my next video?
Hurry up.
Write your guess in the comments section below.
What happens to our body after we die?
It becomes a star.
Not at all.
Doctors declare a person dead when his heartbeat and respiration stops, and his brain is dead.
Once a person is dead, all the muscles in his body relax.
The jaw falls open, eyelids lose their tension and relax, etc.
This state is known as primary flaccidity.
Also, the body begins to slowly lose heat.
The body temperature begins to drop until it matches with the surrounding.
This is known as a death chill.
As the heart has stopped pumping, within minutes.
The blood begins to settle in the lower parts of the body.
Making those parts of the skin appear bluish purple or purplish red.
This is called livor mortis.
Within 3 to 6 hours, the muscles start to contract.
This is known as rigor mortis.
It can last from 24 hours up to 84 hours, after which the muscles again begin to relax.
This state is known as secondary flaccidity.
Now, if the body is burnt, it gets converted to ashes.
Otherwise, the body starts decomposing.
Since the blood circulation and respiration has stopped.
The body can neither receive oxygen nor remove toxic by-products like carbon dioxide.
Hence, these toxic by-products produce an acidic environment inside the cells.
Causing their enzymes to eat their own cells from inside out.
Moreover, we have different microorganisms in our gut, on our skin, etc.
As there is no immune system anymore to control these microorganisms.
They travel to different parts of the body and begin to breakdown the tissues and organs, releasing various gases.
These gases attract insects like flies, maggots, etc. which also eat and breakdown the tissues.
Eventually, a time comes, when only the skeleton is left.
However, over time the skeleton also decomposes.
Topic: Sinkholes.
What causes sinkholes?
Maybe water.
This time you are absolutely correct.
A sinkhole is a depression or cavity in the ground which is caused by water erosion.
Water erosion is a naturally occurring process in which water wears off soil and rocks.
Water is so powerful.
Indeed.
Now listen.
The upper layers of the soil comprise of sand, clay, etc.
While the bottommost layer called bedrock has rocks.
Generally, sinkholes form in places where the bedrock layer has rocks made up of limestone or dolomite.
When rain falls, it seeps into the soil reaching the bedrock.
Over time, the water dissolves these rocks and thus, erodes them forming hollow cavities.
As these cavities get bigger, the ceiling of the cavity.
i.e., the upper layers of soil cannot hold the weight, hence they collapse forming sinkholes.
Why don't spiders stick to their webs?
I don't know.
Usually, a spider's web is made up of silk threads which are covered with droplets of glue.
This glue makes the threads sticky.
Now, when an insect flies through the web, the insect normally gets stuck to the sticky threads.
But, a spider does not get stuck because its legs have tiny hair like structures called setae.
When a spider walks on a sticky thread, the setae gets stuck onto the thread.
Helping the spider to get grip and support to walk.
Now as the point of contact is very less, the glue has very less surface area to stick.
Hence, the spider easily pulls its legs without sticking.
Besides this, a research suggests that certain spider's legs are covered with a special chemical coating.
This coating also helps the legs from sticking to the glue.
How do scars form?
It is a secret process.
I can't reveal it.
No.
It's not a secret process.
A scar is formed when our skin tissue heals itself after an injury.
Our skin tissue has collagen.
Collagen is a structural protein produced by fibroblasts.
Collagen keeps our skin firm and it is usually arranged in a ‘basket weave’ pattern.
Can I use this basket to keep my bags of chips?
Please listen.
When we get injured, our skin tissue gets damaged.
So, in order to heal and close the wound, fibroblasts produce more collagen.
But instead of arranging in a basket weave pattern.
The collagen cross-links and aligns in a single direction.
As a result, the injured area of the skin appears different from normal skin, thus causing a scar.
Topic: Photosynthesis and Transpiration.
Why is the upper surface of a leaf more green and shiny than the lower surface?
Yes.
It is.
You don't believe me.
Why don't you check it?
The upper surface of a leaf is more green and shiny.
While, the lower surface is comparatively less green and shiny.
See, I told you.
Do you know why?
Ok.
Let me tell you.
You must be aware that chlorophyll, which helps the plant to prepare food, is responsible for the green color of the leaves.
But why is the upper surface more green than the lower surface?
This is because the upper surface of a leaf is more exposed to the sun as compared to the lower surface.
Hence, to trap maximum sunlight, there is more chlorophyll on the upper surface as compared to the lower surface.
Hey.
You forgot.
You also wanted to know why is the upper surface of the leaf shinier, right?
It is due to the process called transpiration.
Transpiration is the loss of water from leaves, stems, etc. in the form of water vapor.
Now, to make sure that the plant does not lose a lot of water.
The leaves are covered with a shiny, waxy coating called a cuticle.
But being more exposed to the sun, the upper surface will tend to lose more water.
Therefore, the upper surface of the leaf is covered with a thicker cuticle as compared to the lower surface.
Hence, the upper surface of the leaf is shinier than the lower surface.