Get a feel for hydraulic jack. Using two new plastic syringes (minus the needles) and a few ice-cream sticks you can make a Jack to lift a load. The syringes transit force through the water medium which is not compressible (at least for the purposes of this toy).
This device demonstrates the concept of Mechanical advantage where you can lift heavy loads which little effort. Applying small force over larger distances you lift heavy loads for smaller distance.