LAB REPORT: Demonstrating the Importance of Surfactant
Student’s Name
Institution
Introduction
Surfactant is a fatty, naturally occurring substance found in the lungs. It is an integral part of the respiratory system that helps during respiration. To understand the physiological features of surfactant in alveoli, it is essential to consider the structure and the functioning of alveoli. Thus, the purpose of this experiment is to increase the understanding of the role played by surfactant in the respiratory system. Milk and Food coloring are non-polar and polar, respectively (Sesai et al., 2016). Therefore, I hypothesize that the two will not voluntarily mix. However, by adding washing dish liquid, the two will mix.
Materials and Methods – Briefly state the materials you used and how you did the experiment.
The materials used in this experiment are food coloring (Red, green, blue, yellow), milk, water, penny, and an eyedropper. Water and milk represent moisture in the respiratory system, while food coloring represents respiratory gases.
The methodology involved two Parts
Part 1: Surface Tension
Thoroughly clean penny using tap water and dry it completely. Then place it on a flat surface. Drop several drops of water using eyedropper onto the penny’s surface. Count the number of water drops required to fit the surface until the water starts running off. Record the number of drops.
Part 2: Surfactant
Whole milk was poured in a dish until it completely covered the bottom side. Several drops of food coloring were added in the middle of the milk and observed for two minutes. After two minutes, the distance from the center to the edge of the food coloring was measured. The measurements were recorded in millimeters. Several drops of washing dish liquid were added, and observations made. After two minutes, the distance from the center to the edge of the food coloring was recorded. The measurements were recorded in millimeters.
Results –
After adding 15 drops of the water, formed ball shape until a 16 drop was added that made water to run off. No reaction was observed after adding four drops of food color in the middle of the milk. I then added four drops of dishwashing shop, the food colorings mixed in the milk by running to all different sides. After 2 minutes of the experiment, the measurements were 2.5cm for green, 2cm for blue, 3 cm for yellow, and 3.3 for red. After adding washing dish gel, the measurements were; 5 cm for green, 3.5cm for blue, 4.4 cm for yellow, and 4 cm for red.
Table showing measurements before and after adding washing dish liquid
| color | Before adding in cm | After adding in cm |
| Green | 2.5 | 5 |
| Blue | 2 | 3.5 |
| Yellow | 3 | 4.4 |
| Red | 3.3 | 4 |
Calculations for rate ml/min before adding washing dish liquid
Rate = total length/Tim(min)
10.8/2
5.4ml/min
The calculation for rate ml/min after adding washing dish liquid
Rat = total length/Tim(min)
16.9/2
8.45ml/min
Discussion
From the experiment, more drops were used to fit the penny. This is because water has strong intermolecular forces that hold water together, forming the ball shape. In the second experiment, the length of the food coloring was short and increased when washing dish liquid was added. Also, there was no reaction when food coloring was added at the center of the milk. However, the two mixed up when washing liquid was added. Soap is both polar and non-polar (IncredibleScience, 2014). When it was added, it breaks the magnetic contraction between food coloring and milk, causing them to mix as they did. Similarly, the water in the walls of alveoli is polar while the gas is non-polar. This creates surface tension, the surfactant secreted by lungs aids the two to mix easing respiration process (Sesai et al., 2016). Therefore, dishwashing liquid works similarly with surfactant. The data support this. Before adding dishwashing liquid, the distance was smaller than when the liquid was added. This means that, after adding the liquid, the flow rate increased, causing the distance.
Conclusion
From this experiment, I have proven my hypothesis right that dishwashing liquid would break the tension between milk and food coloring to enable them to mix. I have also understood that liquids have a high rate of surface tension. In our respiratory system, this can be a very fateful thing. But as observed, the body has a natural way to deal with the remedy by secreting surfactant.
References
IncredibleScience. (2014). Milk Food Coloring And Dish Soap Experiment ~ Incredible Science [YouTube Video]. In YouTube. https://www.youtube.com/watch?v=rqQSlEViNpk
Sesai, R., Popa, V., & Marshall, T. (2016). Alveolar surface tension and surfactant: Video | Osmosis. Osmosis. https://www.osmosis.org/learn/Alveolar_surface_tension_and_surfactant