Can time be used as both the x variable and the y variable when
creating a scatter plot?

I want to determine the correlation between the time a company TV
commercial is aired versus the time of day that we receive phone calls.
My objective is to determine which commercials generate the most calls
(we run several different spots per day). I assume I will see clusters
of calls around specific commercials.

I am entering the times in this format: "10:30", "1:15" etc.

Thanks.

-J