top-rated free essay

Lab Report Surfactant

By Myjt2010 Apr 13, 2015 659 Words
Maria Martinez
Anatomy and physiology II
TTH 2:20
“Demonstrating the Importance of Surfactant: Lab Report” Introduction
Surfactant is an essential component for the respiratory system to function properly. This experiment was administrated to help us understand better the role of surfactant in the alveolar system. Surfactant is a detergent-like substance produced by the Type II alveolar cells in the alveoli. Surfactant is produced to make it easier for people to breath by reducing the surface tension of the water molecules that primarily compose the walls of the alveoli; it helps them to not stick together. For this experiment, we will be using milk and food coloring to represent the water (milk) and gas (food coloring) in the respiratory system. Because I know milk is non-polar and food coloring is polar, my hypothesis predicts the two will not mix voluntarily at first, but the soap acting as a surfactant, when added, will help the two liquids mix together.

Materials
(Part on: water surface tension)
1- A penny
2- A dropper
3- Water
4- Paper towels

(Part two: surfactant)
1- Milk
2- 2 different color food coloring
3- Dishwashing soap
4- Cotton swab
5- A mall clear dish
6- Timer
7- Paper towel
8- Water

Method
(Part one: water surface tension)
1- Place the penny in a flat area
2- Fill a dropper with water
3- One by one add the drops of water to the top of the penny 4- Measure how many drops fit until the drops break the surface tension of the water. 5- Record results the results table
(Part two: surfactant)
6- Placed the dish in a flat steady surface.
7- Then poured the milk making sure the whole bottom of the dish is covered. 8- Add four drops of food coloring to the center of the dish. 9- Let it rest for two minutes and then measure how far the coloring expanded. 10- Record in the result chart

11- Dip the cotton swab in soap
12- Place the end of the cotton swab in the middle of the dish containing the milk and the food coloring. 13- Observe what happens to the food coloring and record the result in the results chart. 14- Throw away the liquids and leave station clean after recording results.

Results
(Part one: water surface tension)
The average drops of water that a penny can hold without spilling the water is 24 drops. In my experiment the results were the following: Trial number
Number of drops
Try one
25
Try two
22
Try three
26

(Part two: surfactant)
When the coloring was placed in the milk at the beginning, it didn’t expand through the milk as quickly as when the soap was added. Without the soap
Expanded 5 ml/min from the center.
With the soap
Expanded at 5cm/ sec from the center.

Conclusion
My hypothesis is accepted. After I applied the drop of soap to the milk, the food coloring spread around. Why? At first, the food coloring just sat on the surface of the milk. That's because food coloring is less dense than milk, so it floats on the surface. The milk didn't mix with the food coloring in the beginning because it wasn't stirred together. The soap reduces the surface tension of the milk by dissolving the fat molecules, which is why whole milk works better. The surface of the milk outside the soap drop has a higher surface tension, so it pulls the surface away from that spot. The food coloring moves with the surface, streaming away from the soap drop. Due to the convection that results from the moving surface, the food coloring may be drawn down into the liquid, only to appear rising again somewhere else. When the soap finally gets evenly mixed into the milk, the action stops. If another drop of soap is added, the process starts all over again. This won't work in water because water doesn't contain any fat.

Cite This Document

Related Documents

  • guide to writing research reports

    ...WRITING RESEARCH REPORTS The following set of guidelines provides psychology students at Essex with the basic information for structuring and formatting reports of research in psychology. During your time here this will be an invaluable reference. You are encouraged to refer to this document each time you write a lab report. The writing of ...

    Read More
  • Milk & Food Coloring Lab Report (Importance of Surfactant)

    ...Importance of Surfactant Introduction Surfactant is an essential component for the respiratory system to function properly. Knowing the physiology of surfactant in the alveoli is important to know when learning the structure of the air sacs and how they work. This experiment is designed to make the understanding of surfactant in the alveolar f...

    Read More
  • Lab report

    ...Table of Contents Abstract……………………………………………………………………………………………2 Introduction………………………………………………………………………………………..2 Background………………………………………………………………………...

    Read More
  • lab report

    ...Daphny Maldonado Bio Lab 2107 Kiah Britton W 10-12:30 Is H20 Bad for You? Abstract: In the village of Gopher Hollow there’s a cluster of Blue Baby Syndrome. There were four infants affected by this cluster. The families from the infants would collect their water from wells. We have to determine what’s the source of the high levels of...

    Read More
  • Banana Oil Lab Report

    ... Banana Oil Lab Report Jesse Bradford 7/10/14 MTWR Section Introduction In the banana oil lab we began with isopentyl alcohol + acetic acid  isopentyl acetate + Water. We needed for this experiment a hot plate, clamps, pipette, 5mL vial, caps, hoses and a thermometer. Upon starting, our group set u...

    Read More
  • HISTOLOGY lab report

    ...HISTOLOGY PURPOSE: The purpose of this exercise is to be able to identify and correctly name the major tissue types in the body, as well as identifying the subcatergories of tissue types while observing them through the microscope and diagrams, and be able to explain the location and function of the tissue types in the body. There are not an...

    Read More
  • ka lab report

    ...solution with small amounts of H30+ and A- because only a small amount of base has been added therefore a small amount of ionization has occurred. As we added more base, more HA is ionized and more salt formation occurs meaning the concentration of HA will decrease while the concentration of A- will increase. The pH rises above the equivalence ...

    Read More
  • Fermentation Lab Report

    ...since the fermented product would have more bacteria present. The Gram stain test showed that there were bacteria present in both the Kefir and milk samples, which was not an expected result. Before conducting the experiment, milk was believed to contain no bacteria due to the pasteurization process. Upon further investigation the group came t...

    Read More

Discover the Best Free Essays on StudyMode

Conquer writer's block once and for all.

High Quality Essays

Our library contains thousands of carefully selected free research papers and essays.

Popular Topics

No matter the topic you're researching, chances are we have it covered.