Showing 24 hour time along X-axis

[student_grapher]

Hi there,

I would like to graph sleep times over a period of 2 weeks in a stacke
bar graph. Each bar will represent time fallen asleep and woken up, wit
the length of the bar showing the duration of the night's sleep. I woul
like the X-axis to display clock times in 24-hour time (i.e. starting a
0:00, 0:30, 1:00, 1:30 all the way to 23:30). Can anyone help in makin
the X-axis display in this way?

Thank