Question

Describe the experiment conducted by Jan Baptist Von Helmont and discuss his results in the growth of plant body mass.

Answer 1

1. In the year 1648 a Belgian scientist Jan Baptist Von Helmont conducted an experiment that continued for five years.
2. He took a small willow tree and planted it in a large pot of soil.
3. Before he did the experiment he carefully measured the mass of the dry soil and mass of the tree.
4. He covered the soil with a lid so that nothing could fall on to the surface of the soil and add to its mass.
5. There were holes in the lid so that the tree could grow out of the soil and so that air and water could reach the roots.
6. Von Helmont left the tree for five years giving it only rain water to drink.
7. At the end of five years he measured the mass of the tree and the mass of the dry soil for a second time.
8. The results of this experiment are shown below.

   Mass (Kg)
   	At start	After five years	Change in mass (Kg)
   Tree	2.27	76.74	74.47
   Drv soil	90.72	90.66	0.06