  We observe a solar surge in NOAA AR11271 using SDO AIA 304 image data on 25
August, 2011. The surge rises vertically from its origin upto a height of 65 Mm
with a terminal velocity of 100 km/s, and thereafter falls and fades gradually.
The total life time of the surge was 20 min. We also measure the temperature
and density distribution of the observed surge during its maximum rise, and
found an average temperature and density of 2.0 MK and 4.1 x 109 cm-3,
respectively. The temperature map shows the expansion and mixing of cool plasma
lagging behind the hot coronal plasma along the surge. As SDO/HMI temporal
image data does not show any detectable evidence of the significant
photospheric magnetic field cancellation for the formation of the observed
surge, we infer that it is probably driven by magnetic reconnection generated
thermal energy in the lower chromosphere. The radiance (thus mass density)
oscillations near the base of the surge are also evident, which may be the most
likely signature of its formation by a reconnection generated pulse. In support
of the present observational base-line of the triggering of the surge due to
chromospheric heating, we devise a numerical model with conceivable
implementation of VAL-C atmosphere and a thermal pulse as an initial trigger.
We find that the pulse steepens into a slow shock at higher altitudes that
triggers plasma perturbations exhibiting the observed features of the surge,
e.g., terminal velocity, height, width, life-time, and heated fine structures
near its base.
