Hi guys.

Can you guess the title of my next video?

Hurry up.

Write your guess in the comments section below.

Can you hear colors or see sounds?

No.

But I can eat cakes and watch a movie at the same time.

Alright.

Now listen.

There is a real condition called synesthesia in which the stimulation of one sense triggers an automatic.

Involuntary experience in another sense.

So, when synesthetes hear different tones, they may see different colors.

Or when they see or think certain words, they may experience taste of food items.

Some of them may even associate letters, numbers or words with colors.

We don't actually know why this happens, but researchers think that when we are born.

We have more connections between the sensory areas of the brain.

However.

As we mature, most of the connections are blocked or pruned so that we experience the senses separately.

But in some people, these connections don't get pruned efficiently.

So they may experience two or more senses simultaneously.

What causes dark circles?

A black marker pen.

No.

There are a number of reasons which cause dark circles.

Some of them are stress and lack of sleep.

Under these conditions, our body produces a hormone called cortisol.

Over time.

Cortisol constricts some blood vessels and dilates the others like the vessels around or under our eyes.

As a result, these blood vessels become bigger.

Now,

When sunlight or any white light falls around our eyes.

Various colors which make up white light interact with the skin.

Blood vessels in such a way that they mostly reflect bluish light.

Now, as the skin around our eyes is thinner as compared to other parts of the body.

The big blood vessels that reflect bluish light are prominent.

This makes the area around or under our eyes appear darker, thus causing dark circles.

Why does ice float on water?

To take a sunbath.

No.

It is because of density.

Density is the measure of mass present per unit volume.

Lesser the density, lighter is the object.

Now, every water molecule has two hydrogen atoms bonded to one oxygen atom.

However, besides being attached to its own oxygen atom.

A hydrogen atom is also attracted to oxygen atoms of other water molecules, forming hydrogen bonds.

In liquid state, the hydrogen bonds are not strong.

They constantly break and reform.

Thus, the molecules get arranged in disordered patterns which leave very less empty spaces.

However, when temperature drops below 4 degrees Celsius and ice begins to form.

The hydrogen bonds become strong and stable.

Forming hexagonal patterns which have a large number of empty spaces.

These large empty spaces make ice less dense or lighter than water, causing ice to float on water.

Topic: Auroras

Why are auroras formed?

Maybe because the earth forgets to switch off the lights.

No.

Let me explain.

Our sun is a giant burning star.

It expels tons of solar wind into space.

Solar wind consists of super hot charged particles which are fatal.

So, should we use a big umbrella to protect ourselves from these particles?

No.

The earth's magnetic field acts like a shield and protects us.

Its field lines appear to emerge from the south pole and merge into the north pole.

Now, when the charged particles hit our magnetic field, most of them get deflected.

However.

Some of them flow along the earth's magnetic field lines to the poles and reach our upper atmosphere.

Here, these particles collide with oxygen and nitrogen.

This causes them to give off various colors of light which are called auroras.

Can animals get a sunburn?

Yes.

Due to ultraviolet radiation of the sun, animals can also get sunburns.

However, to protect themselves from the harmful radiation.

Different animals have different biological defenses.

For example.

Reptiles have scales, birds have feathers, animals like sheep, dogs.

Cats have fur or hair, sperm whales have a special protein, fin whales have more melanin, etc.

Does anybody have Captain America's shield?

Please listen.

Some animals even produce certain substances to protect themselves from the harmful radiation.

For example, hippopotamuses secrete a fluid made up of red and orange pigments.

Some fish, amphibians, reptiles and birds produce a chemical called gadusol.

In addition to this, animals like rhinoceroses, elephants and pigs take mud baths.

It is said that mud acts like a physical barrier between their skin and ultraviolet radiation.

Thus preventing them from getting sunburns.