What exactly killed the dinosaurs?

My silly jokes.

No.

Most people believe that an asteroid killed all dinosaurs.

But that wasn't the only reason.

Dinosaurs were already declining due to volcanism, far before the asteroid impact.

Really?

Yes.

Super volcanic eruptions spewed out lava, dust, soot and various gases into the atmosphere.

This triggered a drastic climate change, slowly reducing the dinosaur count.

Then around 66 million years ago.

A 6-mile-wide asteroid crashed into the earth in Yucatán Peninsula.

Hold on.

How do you know?

Scientists found a layer in rocks, called K-PG boundary.

It is rich in Iridium.

Iridium isn't found on earth's surface, but is abundant in asteroids.

Proving that an asteroid crashed the earth.

This caused large rocks to blast into the air and fall back as molten rocks.

Huge tsunamis worsened the condition.

Eventually making dinosaurs extinct.

Topic : Heat transfer.

Why do we use a black umbrella in summer?

Hey.

Looks like you are heading out today.

But it is so hot outside.

Why don't you take a dark colored umbrella, preferably black?

See, I warned you.

At least now use the black umbrella.

Now, do you notice the heat?

No, right?

Do you know why?

This is because in summer season, the temperatures are quite high.

Now, as compared to other colors, a black colored umbrella, being dark, absorbs most of the light.

Ultraviolet radiations coming from the sun and gets heated.

It then radiates the heat back into the air.

Thus, making a black umbrella, a good choice to use in summers.

Topic: Tooth decay.

What causes cavities?

A black sketch pen.

No.

Our mouth contains billions of bacteria which live on our teeth, tongue, etc.

Most of these bacteria are usually harmless.

Just like me, right?

Yes.

Now listen.

A tooth consists of enamel, dentin and pulp.

Enamel is mostly made up of minerals.

Dentin is a layer underlying the enamel.

Whereas, pulp has blood vessels and nerves.

Now, when we eat foods containing sugars, some of these bacteria feed on the sugars producing acid.

This acid starts to dissolve the minerals of the tooth enamel, causing tooth decay.

Usually, our saliva restores these minerals, thus preventing further decay.

But if we continuously eat sugary foods, then our saliva cannot keep up.

Causing the bacteria to pass into the dentin and then eventually into the pulp, thus creating cavities.

What is an allergy?

It is a magic spell.

No.

Allergy is an overreaction of our immune system to usually harmless substances like peanuts, milk, pollen, etc.

These substances are called allergens.

Our immune system has white blood cells or lymphocytes.

Which protect us from foreign invaders such as bacteria, viruses, parasites, etc.

These invaders are called antigens.

When a lymphocyte detects an antigen, it produces antibodies.

Antibodies destroy antigens and thus, protect us.

Now, if an allergen such as pollen is inhaled by an allergic person.

The lymphocytes of the allergic person for unknown reasons think that the allergen is an antigen.

Hence, lymphocytes overreact and produce antibodies which start attacking the allergen.

Besides this, as a protective response, some immune cells also trigger production of excess mucus.

Resulting in running nose.

They even give rise to itching throat and watery eyes, thus causing an allergy.

What is diabetes?

A rare diamond.

No.

Diabetes is a disease in which glucose or sugar levels in our blood remain high.

Is it higher than the Statue of Liberty?

No.

Most of our food is converted into glucose and released into the bloodstream.

Then, our pancreas makes insulin.

Insulin helps glucose get into the cells.

However, in some people, the insulin production is inadequate or it is not used well.

Hence, glucose stays and builds up in the blood.

Increasing the blood glucose level and thus, causing diabetes.

There are three main types of diabetes.

Diabetes type 1 occurs when our immune cells destroy the cells in pancreas which make insulin.

Resulting in less or no insulin production.

Diabetes type 2 occurs when pancreas cannot produce enough insulin.

Our bodies cannot use it well.

Gestational diabetes occurs in pregnant women.

Diabetes can lead to blindness, kidney failure, heart attacks, etc.

Hence, diabetic people should always maintain their blood glucose levels.