Why is a control test tube of water used?
A control test tube of water is used as a reference to compare the results of other test tubes or samples being tested. It serves as a baseline or standard against which the results of the experimental samples can be compared to determine any changes or effects that may have occurred.
The control test tube contains only water and does not have any additional substances or variables that are being tested. By comparing the results of the experimental test tubes to the control test tube, scientists can determine if any observed changes or effects are due to the variables being tested or if they are simply natural variations that would occur even without the presence of the variables.
In summary, the control test tube helps to establish a baseline for comparison, ensuring that any observed changes or effects can be attributed to the specific variables being tested.