"Why is the sky blue?"

Translation: Warum ist der Himmel blau?

[An_droid]

Is there a significant difference between wieso and warum? Wieso is not accepted.

[afarboodi]

Wieso: how so
Warum: why

[DanielDutt9]

Same thing caught me out too. It actually says in the 'questions 2' lesson that warum, wieso, weshalb and weswegen have the same meaning!

[Tats420]

Scattering of short wavelengths.