Question

What is the reason behind the high surface tension of water?

the density of the water molecule helps it to cohere to nearby water molecules , forming a skin over it .
the polarity of a water molecule helps it cohere to a nearby molecule , forming a skin over it .
the weight of a water molecule helps it cohere to a nearby molecule , forming a skin over it ?

Answer 1

Water is H2O.
That means every water molecule has 2 hydrogen atoms, and 1 oxygen atom.

Take a look at the picture I've posted.
Don't worry about all the words. I'll try to make it simple.

The RED circles are OXYGEN.
The GRAY circles are HYDROGEN.

The OXYGEN has a NEGATIVE charge.
The HYDROGEN has a POSITIVE charge.

Now, do you see how every molecule of water looks bent into an angle shape?
That's why it's POLAR.

Water molecules wouldn't be polar, if they didn't look bent.
But water molecules are bent. And this makes them polar.

And water molecules can stick to each other easily, because they are polar.

The negatives and positives all stick to one another.