As the air in contact with the sand begins to heat up, it expands and rises.
(the air in contact with the sand; begins; ) (the air in contact with the sand; to heat up; ) (it; expands; T:As the air in contact with the sand begins to heat up) (it; rises; T:As the air in contact with the sand begins to heat up)
the air in contact with the sand the air in contact with the sand it it
begins to heat up expands rises
T:As the air in contact with the sand begins to heat up
T:As the air in contact with the sand begins to heat up