Using Surfactants to Analyze Surface TensionBy: Paige GarciaMrs. La SalleChemistry period 3

Purpose• To observe the water property of surfactants of a

substance that interferes with hydrogen bonding between water molecules reducing surface tension.

Materials• Shallow Dish• Water• Paper Clip• Rubber Band• Syringe• Vegetable Oil• Liquid Dish Detergent

Materials Continued

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Conclusion/Analysis Part One

Surface tension is exemplified in step 3 of this lab. By placing the paper clip onto the water, water molecules began to pull inward. That inward force reduced the surface area of the water creating surface tension allowing the paper clip to float. Oil acted as a surfactant in this lab. Once the oil was placed in the center of the rubber band, it interfered with the hydrogen bonding between the water molecules which reduced the surface tension. Possible sources of error from this lab could be how the some of the oil went outside of the rubber band.

Conclusion/Analysis Part Two• 1. The paper clip displaced the water. (Similar to a human in

a bath tub)• 2. A paper clip doesn’t float when it gets wet but when

placed in to water, a paper clip does float because of the surface tension. Once placed, water molecules at the surface tend to be drawn inward. The inward force tends to minimize the surface area of the water allowing the paper clip to float.

• 3. The rubber band expanded to nearly its entire diameter when the water inside of it was covered in oil because the oil ( a surfactant) interfered with the hydrogen bonding between the water molecules.

• 4. When the dish detergent was dropped onto the layer of oil the dish detergent slowly sunk until it was under the oil.