How do hydroponics work?
 

I'm a student and I am conducting an experiment. I was wondering; How do hydroponics work? How do you grow a hydroponic plant?

A submersible pump comes on and pumps nutrient enriched water to plant roots that are grown in a number of inert materials as expanded clay aggregate (grow rocks), spun volcanic rock (rockwool), perlite, pores gravel, lava rock, or as with some hydroponic systems, no medium at all.