The Function and Importance of Surfactant: Lab Report

Introduction

The purpose of this lab report is to demonstrate the function and importance of surfactants using household products. Surfactants play an important role in the respiratory system, whereby they coat the alveoli walls of the lungs (National Library of Medicine - NLM, 2017). According to the NLM, the ability of surfactants to coat the alveoli walls is rooted in their surface tension reducing capabilities. Two experiments were performed - whereby the first experiment was to observe surface tension created when drops of water are dropped on a penny and determine why a penny could hold so many drops of water before it ran off. The second experiment was performed to observe whether surfactants indeed counteract the properties of water by lowering surface tension of water molecules, and whether the absence of a surfactant could have an effect on the respiratory system. This is more so the case given that as the NLM (2016) points out, the ability of surfactants to lower surface tension is largely dependent upon the concentration of the surfactant on the surface of the alveoli. Therefore, when the concentration of surfactants is low, it would diminish the pressure to inflate the alveoli at exhalation leading to breathing problems (National Library of Medicine, 2017).

Materials and Methods

Two experiments were carried out using household products to demonstrate the importance how surfactants work. The first experiment, which involved surface tension, was first carried out before the effects of surfactant could be explored. In this experiment, a penny was first washed, rinsed, and dried with a paper. A clean eyedropper was filled with tap water. The dry penny was placed on a flat surface, and individual drops of water dropped on the surface of the said penny until the water ran off the penny. The individual drops of water dropped on the penny before water could run off the penny were then counted and recorded.

In the second experiment on the effects of surfactant, a clean shallow dish was placed on a flat surface and whole milk poured on it until it completely covered the bottom of the said dish. Second, a couple drops of food coloring were added to the milk using an eyedropper. The solution was then observed for two minutes. After the given timeframe elapsed, the distance from the center of the food coloring to the edge of food coloring was measured in millimeters using a ruler. Thereafter, the rate of movement per minute was calculated to determine the rate in millimeters per minute.

In the above solution, a couple of drops of dishwashing liquid were added drop-wise from the center of the dish. Two minutes later, the milk and the food coloring were observed and the distance from the center of the food coloring to the edge of the said food coloring measured in millimeters. The rate of movement per minute was also calculated to determine the distance in millimeters per minute.

To control the possibility of the dishwashing liquid reacting with the milk and food coloring in the second part of the surfactant experiment, a control experiment was performed whereby food coloring was added to the dish of...…surface tension. This is more so the case given that the dishwashing liquid was able to reduce the surface tension of milk and allowed it to interact with the food coloring.

When compared to the respiratory system, the milk would act as water which has high surface tension, the food coloring would act as the gas in the respiratory system, while the dishwashing liquid would function as the fluid that coats the alveoli walls of the lungs, which is a surfactant. Therefore, if the surfactant was absent, Han and Mallampalli (2015) points out that the alveoli walls of the lungs would not be coated given that the surface tension at the water and the gas interface would still be high - preventing them from interacting. As a Consequence, the entire process of respiration would be disrupted given that the alveoli would collapse at the end of expiration (Han and Mallampalli, 2015). According to the authors, a condition known as atelectasis would occur during breathing owing to high surface tension in the alveoli.

Conclusion

The effect and role of surfactants depend on their ability to lower the surface tension of water which happens to be high. The said surfactants lower the surface tension of water thus ensuring that the gas and the liquid interface interact. Essentially, the dishwashing liquid which acted as a surfactant was able to reduce the surface tension of milk which made the milk and food coloring interact. However, it would be prudent to note that since surfactants play a major role in lowering surface tension in respiratory system, their absence may be detrimental to…