MARTYN F. CHILLMAID / SCIENCE PHOTO LIBRARY MARTYN F. CHILLMAID / SCIENCE PHOTO LIBRARY
Vacuum chamber gauge. Close-up of the gauge on a vacuum chamber, showing the pressure reading in hectopascals (hPa). The hectopascal (100 pascals) is the SI unit equivalent of the millibar. Atmospheric pressure is just over 1000 hPa, equivalent to 1000 millibars, or 1 bar. The pressure shown here is slightly below atmospheric pressure.
Model release not required. Property release not required.