Microfluidic device and uses of teaching scientific principles

A microfluidic device comprising:

• a first microcapillary, wherein the first microcapillary has an end region having a J-hook shape comprising a semicircular curved portion extending from a straight section of the first microcapillary, wherein the first microcapillary has an inlet, wherein the inlet is at an end opposite the end region having the J-hook shape, wherein the end region of the microcapillary has an outlet, wherein the outlet is at an end opposite the end with the inlet, wherein the outlet of the first microcapillary is at a lower height than the inlet in the microfluidic device;
• a reaction chamber, wherein the reaction chamber has an inlet and an outlet, wherein the inlet of the reaction chamber is coupled to the outlet of the end region of the first microcapillary, wherein the inlet of the reaction chamber is positioned at a height lower than the outlet of the reaction chamber in the microfluidic device, wherein the reaction chamber has a greater width than the first microcapillary;
• and
• a second microcapillary, wherein the second microcapillary comprises an inlet and an outlet, wherein the second microcapillary is serpentine shaped with a path that reverses direction in at least one region between the inlet and the outlet of the second microcapillary, wherein the inlet of the second microcapillary is coupled to the outlet of the reaction chamber, wherein the inlet of the second microcapillary is at a lower height than the outlet of the second microcapillary in the microfluidic device.