1.04 Properties of Water
Question: What effect will adding soap to water have on surface tension?
Hypothesis: If, soap is added to the water slowly dropped on a penny then, the penny will hold more water.
Independent/Dependent/Control Variables: Independent: the amount of soap/oil; Dependent: the penny; Control: amount of oil/water given
Materials: 3 cups, water, canola or olive oil, dish soap, a pipette and or needle/syringe, pennies
Procedure:
· Gather three identical cups
· Add water to the first one (1/3 cup of water in each), add water and soap in the second one, and olive or canola oil in the third.
· Lay out three pennies.
· Take pipette and slowly bring water in from cup #1, drop onto penny until water falls over, record results of how many drops it took.
· Repeat with cup numbers 2-3 and record information/data.
Data/Observations: With the regular water on a penny, I noticed that only 13 regular drops could fit on without falling over.
With the water+soap, it got up to 24 drops before falling over. Then on the 25th drop, the mixture fell off.
With the oil, it was the highest at 29 drops before falling over slowly. Therefore, oil holds the most surface tension in this experiment.