Hydraulic systems for Danny

Danny asked me recently where all the power comes from a crane is using,just one many questions our kid is asking daily.
We went on the Youtube side to seek for a easy understandable illustration of a hydraulic system:

Hydraulische Hebebuehne
Daniel watched the video twice and was asked to explain us how the whole systems operates to ensure that he apprehended the lesson of technical operating modes.:)

Using the internet for education is like living in a huge library instead of placing a curious by nature kid in front of a TV.If you want smart kids throw the TV out first.:)