This paper gives results of an experimental study to determine the effect that a surface reaction has on a boundary layer flow. An innovative technique has been developed to visualize the effect a surface reaction has on a flat plate boundary layer flow. A mixture of mineral oil and hexanoic acid flowed at low Reynolds number over a metal plate embedded with a small piece of sodium. The reaction between the hexanoic acid and the sodium metal produced hydrogen bubbles, which rose to the surface. Upstream of the reaction, dye was injected into the laminar flow, and the interaction between the bubbles and the dye was recorded. Results show that bubble entrainment stretch and bend the dye filaments, convect fluid away from the reaction, and create vortices downstream and to the sides of the reaction. These results show that a surface reaction can introduce velocity fluctuations into an otherwise laminar flow. Farther downstream the flow relaminarizes.