Meaning of WHAT ON EARTH? - A Really Short English Lesson with Subtitles

So sometimes in English we add the words, "on earth", to a question for emphasis.

So we might say something like, "What on earth are you doing?"

If someone was doing something that we thought was odd or strange, we might say, "What on

earth on are you doing?"

We can also add it to questions with how.

We can say, "How on earth did you solve this math problem?

I worked on this problem for a long time.

How on earth did you figure it out?"

You might even use it when you're asking someone why, you might say, "Why on earth did you

put so much salt in this recipe?

It is way too salty now!

Why on earth did you do that?"

And you may even use it for where, like, "Where on earth did you find that awesome t-shirt?

That is such a nice shirt.

I was just wondering where on earth did you find it?"

Just for emphasis!