No-till farming will decrease the soil loss on hills of similar steepness as compared to the
traditional farming technique because there will be less disturbance to the soil.
A hypothesis can be either proved or disproved by testing. If a hypothesis is repeatedly
tested and proven to be true, then scientists will no longer call it a hypothesis.
Experiment
Not all questions can be tested by experimentation. However, many questions present us
with ways to test them that give us the clearest conclusions. When we design experiments,
we select the factor that will be manipulated or changed. This is theindependent vari-
able. We will also choose all of the factors that must remain the same. These are the
experimentalcontrols. Finally, we will choose the factor that we are measuring, as we
change the independent variable. This is thedependent variable. We might say that the
dependent variable “depends” on the independent variable. How much soil is eroded depends
on the type of farming technique that we choose.
Figure 1.4: A farmer takes careful measurements in the field. ( 13 )Example:The farmer will conduct an experiment on two separate hills with similar slopes
or steepnesses (Figure1.4). On one hill, he will use a traditional farming technique which
includes plowing to stir up the nutrients in the soil. On the other hill, he will use a no-
till technique by spacing plants further apart and using specialized equipment that plants
the plants without tilling. He will give both sets of plants identical amounts of water and
fertilizer.
In this case, the independent variable is the farming technique—either traditional or no-
till—because that is what is being manipulated. In order to be able to compare the two
hills, they must have the same slope and the same amount of fertilizer and water. If one