Biology 11–12 · Year 12
Water treatments compared by plate counts: boiling, chlorination and filtering
Module 7: Infectious Disease (Prevention, Treatment and Control)
Teacher-led demonstration
A teacher carries out this activity as a demonstration. Its materials, steps, variables, misconceptions and sources are not published on the open web, and neither is any result, control or note that states a number or an amount: tutors and administrators read them on the learning platform, with the safety card first. The idea, the hazards and the curriculum references are below.
Open the procedure on the learning platform (tutor or administrator sign-in)
School laboratory, not for home
In a school laboratory, with a teacher supervising, under the school's risk assessment. Not for home.
The idea
Treatments that kill or remove microbes reduce the number of colonies a water sample can grow, and plate counts before and after measure how well each treatment works.
Safety card
Setting: In a school laboratory, with a teacher supervising, under the school's risk assessment. Not for home.
Hazards
- Environmental water may carry pathogens and cultures concentrate them
- Boiling water scalds
- Bleach is corrosive to eyes
- Bunsen flame and ethanol
Controls
At least one of them states a number or an amount, which may be part of the method, so the controls are shown with the method to tutors and administrators on the learning platform.
Note
It states a number or an amount, which may be part of the method, so it is shown with the method to tutors and administrators on the learning platform.
What you should see
It states a number or an amount, which may be part of the method, so it is shown with the method to tutors and administrators on the learning platform.
Curriculum references
The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.
- Biology Stage 6 Syllabus (2017), current: Year 11 taught to the end of 2026 and Year 12 to Term 3 2027BIO12-14BIO11/12-2BIO11/12-3BIO11/12-4
- Biology 11–12 Syllabus (2025), Year 12 focus area Diseases; new syllabus not yet taught: Year 11 from Term 1 2027, Year 12 from Term 4 2027BI-12-02
- Biology 11–12 Syllabus (2025), Year 12 Working scientifically; new syllabus not yet taught: Year 11 from Term 1 2027, Year 12 from Term 4 2027BI-12WS-02BI-12WS-03BI-12WS-04BI-12WS-05
- Australian Curriculum v9No Australian Curriculum v9 code is listed.