Roots also stabilize the plant, and keep it from being blown or washed away. To be valid, experiments must test a single variable by comparing against the standard or control. Leaves grow out of the stem. Students propose a hypothesis and design an experiment to test their hypothesis. They predict what will happen when a single plant growth condition is changed.
Students conduct an experiment.
Using a hydroponics system they've built, they plant seeds and compare their control plants against the experimental variable. The scientific method of proposing hypotheses, designing and carrying out experiments and drawing conclusions based on their results. The key to growing plants hydroponically is to provide everything the plants need. Plants have the same requirements for growth regardless of whether they are grown in soil or hydroponically, indoors or out. Without any one of these essentials, the plant will die.