Cool apps

오늘은 달리기 하는 동안에 이 앱을 해 봤어요. 재미있어요. 저는 다른 앱을 해 볼 것 같아요
(Today while running, I tried this app. Interesting. I think I'll try other apps)
While/when - are they interchangeable in Korean like they are in English?
Example: when I was running. While I was running

오늘은 달리기(를) 하는 동안에 이 앱을 해 봤어요. 재미있어요. 저는 다른 앱을(or 앱도) 해 볼 것 같아요.(or 해 볼래요/ 해 보겠어요)
(Today while running, I tried this app. Interesting. I think I'll try other apps (as well))

While/when - are they interchangeable in Korean like they are in English?
Example: when I was running. While I was running

Yes, Susan. They are interchageable. Please look at the followings

I found out these information/descriptions from English dictionary.

while (conjunction) http://www.ldoceonline.com/dictionary/when
1. during the time that something is happening:

when (adverb, conjuction, pronoun) http://www.ldoceonline.com/dictionary/when
2 at or during the time that something happens:

Thus,

Today while running, I tried this app.
저는 오늘, (제가) 달리기를 하는 (시간) 동안에, 이 앱을 해 봤어요.

while (I was) running = durning the time that I was running, ※ 동안(에), during the time

Today when I was running, I tried this app.
저는 오늘, (제가) 달리기를 할 때에, 이 앱을 해 봤어요.

when I was running = during the time that I was running

I've learned the usages of conjunction "when/while/as" from this link.
http://www.grammarbank.com/when-while-as.html

So, Sunan, I think you can also learn some useful linguistic/grammar terms from there. If you learn those linguistic terms, you can easily understand Korean grammar, by comparing the difference between English and Korean.
http://www.grammarbank.com/english-grammar-lessons.html