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How do we know that our stomach is full?

Usually, our stomach and brain are constantly communicating with each other.

With the help of hormones and nerves.

So, when our stomach is empty and the glucose level in our blood is low.

The stomach produces a hormone called ghrelin.

Ghrelin generally travels to the brain through blood and informs the brain that we need to eat and thus, we feel hungry.

Now, when we eat food to satisfy our hunger, the food enters our stomach, causing its walls to stretch and expand.

When this happens.

The nerves on the stomach walls detect the expansion and tell the brain that our stomach is full and our hunger is satisfied.

However, our stomach also expands when we drink a lot of water.

But in this case, our hunger is not satisfied.

Do you know why?

This is because there is one more method by which our brain can identify whether we are eating food or just drinking water.

Can you guess what that method is?

Alright.

I'll tell you.

As mentioned earlier, our stomach and brain constantly communicate with each other with the help of hormones.

One of these hormones is cholecystokinin.

When we begin to eat.

Nutrients in food stimulate the release of cholecystokinin which eventually enters the bloodstream.

It is the presence of this cholecystokinin in the blood.

Which informs the brain that we are eating food and not just drinking water.

Now, as we eat more food, more cholecystokinin is released.

Informing our brain that our stomach is getting full with food.

Thus, the brain needs to suppress the desire to eat.

Last but not least, did you know that boiled potatoes are the most hunger satisfying foods.

So, next time if you are hungry try them and find out the truth.

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.

Or 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.

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 do dogs lick their wounds?

Dogs including animals like cats, chimpanzees, rodents, etc. don't have access to a proper medical treatment.

Hence, a little licking helps to heal and clean the wound.

What?

But how?

When dogs lick, they apply saliva on their wounds.

This saliva has antiviral and antibacterial compounds like an enzyme called lysozyme.

Lysozyme destroys cell walls of certain bacteria and helps kill them, thus preventing infection.

The saliva also contains a protein called tissue factor which promotes blood clotting and thus stops bleeding.

Besides this, licking also removes dirt from the wound.

So, dogs should always lick their wounds.

No.

Excess licking is not beneficial.

This is because a dog's saliva can also contain harmful pathogens.

They could aggravate the wound and make it more painful.

Hence, now a days, dogs are made to wear an Elizabethan collar to prevent them from licking.

How do x-rays work?

It's confidential.

No.

X-rays are very high energy waves.

They were accidentally discovered by a physicist named Wilhelm Röntgen.

As he did not know what they were, he named them ''X-rays''.

X-rays can pass through many objects but if an object's density is more, then these rays get absorbed and don't pass.

Due to this property, X-rays are used to detect fractures, tumors, etc.

To detect a fracture, x-rays are passed through our body which then hit an x-ray detector or a photographic film.

Now, since our tissues are not dense enough, much of the x-rays pass through them and get detected by the film.

Thus casting a dark or grey shadow on the film.

But as the bones are much denser, the rays get absorbed and hence, the bones appear white on the film.

This allows doctors to have a look at the structure of bones and thus, spot the fracture.

Topic: Oxidation.

Why do papers turn yellow?

They really do.

You don't believe me?

Alright.

Then why don't you spray some oxygen on the papers?

See, I was correct.

Do you know why this happens?

This happens mainly because of oxidation.

Oxidation is a chemical process in which a substance combines with oxygen.

Now, paper is primarily made up of wood.

Wood is made up of cellulose and lignin.

Now, these two components which are present in paper are susceptible to oxidation.

i.e., when they are exposed to air, they are likely to combine with oxygen.

Causing the color of paper to change from white to yellow.

But did you know that newspapers turn yellow relatively quickly as compared to books?

This is because there is more lignin in newspapers than in papers made for books.

Lignin is more susceptible to oxidation as compared to cellulose.

Hence, newspapers turn yellow faster than papers of books.