あしたなにをしますか。
あしたはなにをしますか。
Hi everyone! I want to know if there is any difference in the meaning for the above sentences?
は defines the theme of the sentence (the subjected that is talked about) so it might add a nuance of contrast.
明日は何をしますか。
means "what will you do tomorrow?" in the sense of "about tomorrow, what are you going to do?".
明日何をしますか。
This one however just means a neutral "what will you do tomorrow?".
Depending on the context, for example if you were talking about what you were doing the days before, the は in 「明日は何をしますか」 can imply that you will probably do something different the day after. The same sentence without は has no such nuance.
If you want to go further, Jay Rubin's Making Sense of Japanese explains the は concept very clearly.
