Investigatory Science Projects With Soap & Oils
- When oil spills into the ocean, it has devastating effects on marine wildlife, particularly birds. To demonstrate this, students should collect feathers from outside the school and dip them into standard kitchen vegetable oil. They should then be asked to clean the feathers with running water. They will find it almost impossible to remove the oil. They should then be asked to add a liquid-based soap. The soap causes the oil to mix with the water, making it far easier to remove.
- One of the reasons an oil spill has such devastating consequences for wildlife is that it spreads incredibly far. The above experiment can be adapted for an older age group to assess how soaps can be used to aid in the cleanup of vast spills. To begin, water should be poured into two bowls and vegetable oil added. A thin layer of oil will form on the surface of the water, because water and oil will not mix. A few drops of a liquid-based soap should then be added to one of the bowls and its effect on the oil recorded. Using a variety of materials, such as cotton balls, paper towels and a sponge, students should try to collect the oil to assess which material works best. After an oil spill, massive sponges, called sorbents, are used to collect oil in this way.
- Another way this experiment can be adapted would be to examine the various ways oil spills are cleaned up. Often, oil is collected with long booms and skimmed off the top of the surface of the water. A dispersant can be used on its own, as the oil will eventually break down if left long enough. In seawater, nitrogen and phosphorous can be added to encourage bacteria to grow that in turn degrade the oil. Students could compare these methods with the one described above.
- In this experiment, old cooking oil can be used to make soap. Students should carefully weigh 20 grams of caustic soda, or sodium hydroxide, on a piece of folded paper without touching it. This should then be added to a mixture of 125 cm3 of vegetable oil and 100 cm3 of water and stirred constantly. Eventually, a thick paste will form, which could take up to 30 minutes. If it takes any longer than this, add four spatulas of salt. If desired, add essential oil or perfume. This paste should be poured into a mold and left to set for a few days. The result is a crude version of soap, ideal for washing clothes, equipment or perhaps your hands (but definitely not your face as sodium hydroxide is still present).