To investigate whether roots exert a pushing force strong enough to cause water to move up the stems plants, my question is state and explain 4 precautions to be considered during the setup of this experiment

The root of the plant must be tightly packed into the glass tube and fixed with a cork.
The plant must be uprooted from at least 3-4 cm above the soil surface.
Initial water levels and final water level must be carefully noted.
Observe the presence of water droplets on the leaves. 
Leaves must be removed form the portion which is fixed into the glass.

Um can u take a picture of the work