Experimant! This is how a hydro pump storage power station (eg, Ben Cruachan by Loch Awe) works.
Need: 1 glass of full water. 1 sausepan. 1 straw.
1) Pour the water over your finger into the sausepan
2) Suck the water back into the glass
3) Repeat this until your board of it
Notes: This is how a hydro station works. First the water falls down from a reservoir hitting the turbine so it generates electiricty that gets sold to the national grid. At night the water gets pumped back up when the electricity is cheaper to buy.