Where do Plants Get their Food?

At one time, it was believed that plants got their nutrients and food directly from the soil. Some scientists became skeptical of this and proposed an alternate method by which plants get the food necessary to grow. They thought that plants used sunlight to create the food needed for life processes. Everyone laughed at such a silly idea. How could the sun give anything food? These scientists were convinced, but they had to first disprove that present idea that the plant's food came from the soil. They would have to design an experiment to show that the soil was not actually "consumed" by the plant as it grows. Experiments were based on the idea that if the plant was actually consuming the soil as part of its diet, then the amount of soil in a potted plant would decrease over time as the plant grows.

Consult with your lab partner to design an experiment that will disprove the idea that plants obtain their food from the soil. You will have the following materials available to you to conduct your experiment.

4 bean seedlings (bean seeds just beginning to sprout)
2 cups or plant containers
Soil
Balance of Scale

Describe your experiment. Make sure your design can answer the following questions:

How will you tell if the plant(s) have actually consumed the soil?

Do you have a control? What is the purpose of the control?

Set up your experiment. And design a data table that will record data over a two week period.

After you have collected your data, you will write your conclusions and answer the question: Did the plants consume the soil? How do you know?