In some areas, such as in mining and industry, detecting even the smallest stream of air is very important, in order to dependably assess the possible spread of hazardous substances. With a simple system of tubes, the source, direction, and velocity of air movements are immediately made visible.
The air flow testing tube can be used until the ‘white smoke’ has fully escaped. If the test has been completed in advance, the tube with its rubber cap can be closed again.
The tube contains sulfuric acid fumes. When the ends of the tube are opened, you pump air through the tube with a small rubber ball. Then, visible white smoke appears that is carried through any streams of air that are present.