Hypothesis: The lowest priced soap should have least Ph difference while the more expensive ones should have a higher PH difference.
Method: First we note the price of each brand of soap and cut bits off the soap. Then we measure the bits. We place the piece of soap in beakers and fill it with water. We fill another beaker with water. After a week we check the ph of the beaker mixed with bits of soap and the ph value of the beaker with plain water. We do this likewise for all brands of soaps. Then we must calculate the difference between initial ph of the water and the final ph.
Materials required: 30*2 Beakers, Water, 30 Different brands of Soap, Blade (for cutting soap) and a weighing scale.
Qualitative data: After keeping the soap in water I noticed that the soap particles would often get discoloured inside water. This usually occurred with soaps from high, expensive brands while in the cheaper soaps, the particles would not get discoloured.
The data has been processed by the following method:
Ph Difference= Initial PH-Final PH
The method to calculate the value of the soap compared to the difference in Ph is done by dividing the price of each soap by its weight per gram.
X- AXIS (Horizontal)- price of soap
Y- AXIS (Vertical)- change in pH
Method Sourced from: “Mathematical Studies by Stephen Bedding via Oxford University Press”. Graphed and Correlation done via Microsoft Excel 2010.
Discussion: The Correlation Coefficient shows a very weak positive. This is the change in the PH of water on adding the soap to it. There is a major cluster around the range of 0.3 and the brand OLAY had the highest difference in PH value.
The slope of the graph tells us that the responsiveness is high and the price of soap and the change in pH do seem to have some sort of relation. Although the graph shows a fine trend line but there are some points which are quite far apart, in the graph these are ignored as such which could have been significant. Hence the graph isn’t very reliable.
The price of soap is not always only dependent on quality. Factors such as brand name, market share, sales, manufacture approaches and promotion also come into play. Therefore it is not very easy to bring out a clear relation between the two.
Strengths: Ph meter is accurate. The amount of water it is dissolved in is the same in all.
Weaknesses: Soap settles at the bottom so it doesn’t dissolve properly. Leaving beaker out in the open may cause problems like dead bugs. Some brands of soap react differently to water. Some dissolve and some have to be cut up. Some Soap brands may not be so good but may have higher prices due to importing costs or simply because they are reputed brands.
Conclusion: The Correlation Coefficient shows a Very Weak positive. Therefore, we can conclude that the price does somewhat affect the change in PH. The more expensive brands seem to be intent on hurting the environment (higher changes in PH values) while the cheaper brands and even some of the mid-range brands (Camay Park, Park Avenue) seem to have less detrimental effect.