Factors affecting the effectiveness of soap - Coggle Diagram
Factors affecting the effectiveness of soap
Equation of Reaction: Fat + Lye -> Soap + Glycerol
Soap is a cleansing agent created by the chemical reaction of a fatty acid with an alkali-metal hydroxide. Chemically speaking, it is a salt composed of an alkali-metal, such as sodium or potassium, and a mixture of “fatty” carboxylic acids.
The oil comes from an animal or plant, while the alkali is a chemical called lye. In bar soap-making, the lye is sodium hydroxide. Liquid soap requires potassium hydroxide.
How to measure effectiveness of soap:
The effectiveness can be measured by using agar plates. Use the different soap bars on dirty hands, then swab the hands and swipe onto the petri dishes. Then place into an incubator to see how much bacteria growth in each plate.
Factors affecting soap
Concentration of lye in soap
Water is used to dissolve sodium hydroxide lye so it can react with the oils and start the saponification process. As the soap cures, the water evaporates and creates harder, longer-lasting bars. Lye needs at least an equal amount of water to form a solution. Various sources recommend a ratio of 2 parts of water to 1 part of lye.
Possible Hypothesis: As the concentration of sodium hydroxide increases, the growth of the bacteria will decrease.
Amount of substances used
Mixing speed and duration of mixing
Concentration of oils and fats
Hard to control factors
Different soapmaking oils
Hard Oils (hard bar of soap)
Brittle Oils (hard bar of soap)
Palm Kernal Oil
Soft Oils (softer soap)
Easy to control factors
Type of oil
The dependent variable is the effectiveness of soap, measured by the growth of bacteria on the petri dish.
The independent variable is the different concentrations of Sodium Hydroxide.
Controlled: Type of dirt and Temperature
List of Risks:
Boiling the soap
Glassware which could break
List of Limitations:
Given time frame to conduct practical
Incubation period too short
Lack of precision for boiling