SciFest National Final 2023

Stand 15

The Effects of Hard Water on Hair

Student Gabriela Giuliese
School Blackrock Educate Together Secondary School, The Sandymount Buildings, Simmonscourt Road, Ballsbridge, Dublin 4
Teacher Katie Burrowes
Venue TU Dublin Tallaght


To identify the effects of hard water on the hair.


Hard water is found in over 70% of Irish households. Hardness is determined by the amount of salts, calcium carbonate or magnesium sulphate, dissolved in the water. The build up of salts produces a film on the hair, making it difficult for moisture to penetrate, weakening the hair.


Hair strands were collected from a total of 50 volunteers within different age groups, hair colour and type. The hair strands were immersed in different types of hard water with different concentrations. The tensile strength was tested using a Newton meter and a material testing machine. The strands were also examined under a microscope.


In method 1 using a Newton meter, magnesium sulphatehard water had a weak correlation with the hair strength (0.0034 R2). Calcium carbonate hard water had a more noticeable correlation (R2 = 0.038). Mixed hard water had the highest correlation in comparison to the previous ones (R2 = 0.1022). In method 2 a material testing machine was used to generate a stress-strain curve for the hair sample immersed in the mixed hard water. The hard water had very little effect on the yield strength (R2 = 0.0065), the Young’s modulus (R2 = 0.0025) or the tensile strength (R2 = 0.1812).


A strong correlation between hard water with different concentrations and the tensile strengh of the hair could not be found. There was a noticeable pattern on the hair cuticle, indicating that hard water does have an effect on the hair cuticle.

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SciFest National Final 2023
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