The pressure of both tanks were 117.7 kpa.( first picture)

We added 500kg mass to the left tank and the pressure went up to 118.7. (second picture)

Can you explain why the pressure changed after adding the 500 kg mass?

 

Image transcription text

Fluid Pressure and Flow (1.02) X File Help Pressure Flow Water Tower PHET Ruler Pressure Grid -
Atmosphere 101.300 kPa On Off - Units @ Metric Atmospheres O English Reset All 500 kg X 250 kg
250 kg Pressure Pressure - 117.7 kPa 117.7 kPa Fluid Density 1349 kg/m 3 gasoline water h... 

Image transcription text

Fluid Pressure and Flow (1.02) X File Help Pressure Flow Water Tower PHET Ruler Pressure ? Grid -
Atmosphere 101.300 kPa @ on Off - Units Metric Atmospheres English Reset All X 250 kg 250 kg 500
kg Pressure Pressure - kg/m 3 118.7 kPa 118.7 kPa Fluid Density 1349 gasoline water honey...