Why is it difficult to form alum in the coagulation experiment?

Everyone knows that the formation of alum blooms in the coagulation experiment is an important factor in the quality of the test. Often the alum blooms are large and dense to show that the precipitation effect of the coagulation experiment is good, and many new users will cause

How to wire with switch socket?

When the home is renovated, the installation of the switch socket in the room is an indispensable part, but in the installation process, how to wire it, there are still many details.

First, sw