Osmosis(possibly physics and biology ) and Pressure understanding help?

The osmotic pressure is the pressure of the water to get from one side to the other. If you put the hypertonic and the hypotonic solutions on both sides of a membrane that lets only water get through, the water will "push" to get through, thus creating the pressure. You'll see the hypertonic side become more filled, the level is higher. That difference in level illustrates osmotic pressure (as pressure = g . h . m/V, h being the level difference).