Quick build and test of a Lego pump that sucks air. It can generate a 70% vacuum.
At the end I show another Lego way to create vacuum: Lego pneumatic pump pushing air out of a jar. This can generate a 63% vacuum. Water boiling test to prove the gauge was correct. Enjoy!

0:00 Build
1:23 Test
1:55 Test boiling water
2:27 Another build and test

LINKS
Lego Pneumatic Cylinder V2 2 x 11 https://www.bricklink.com/v2/catalog/...
Lego Pneumatic Pump Small (6L) V2 with Reinforced Cylinder https://www.bricklink.com/v2/catalog/...
Lego Pneumatic Switch with Pin Holes and Axle Hole https://www.bricklink.com/v2/catalog/...
Lego Hose Pneumatic 4mm D. V2 https://www.bricklink.com/v2/catalog/...
Vacuum Pressure Gauge https://www.amazon.co.uk/dp/B07WK3CD2M/
Temperature Sensor PMTEMP2 https://www.amazon.co.uk/VellemanPMT...