Learning More About Water Purification

Basic Science and Technology

Primary 3.

2nd Term

Second term


Week: Ten

Class:Primary Three

Topic: More about water purification

Behavioural objectives:At the end of the lesson, pupils should be able to:

1. practicalize

2. practical.

Instructional material/Reference material:Stove, Water, Sieve cloth, TCP

Building Background /connection to prior knowledge: pupils are familiar with water condensation and it process.



Ways of water purification

BOILING: Boiling is sufficient to kill pathogenic bacteria, viruses and protozoa (WHO, 2015). If water is cloudy, let it settle and filter it through a clean cloth, paperboiling water towel, or coffee filter. Bring water to a rolling boil for at least one minute.

FILTRATION: Filtration is the process of separating suspended solid matter from a liquid, by causing the latter to pass through the pores of some substance, called a filter. The liquid which has passed through the filter is called the filtrate. Water flows through a filter designed to remove particles from within it. The filters are made of layers of sand and gravel, and in some cases, crushed anthracite. Filtration collects the suspended impurities in water, enhancing the effectiveness of disinfection.

ADDITION OF ALUM: Alum (aluminum sulfate) is added to the water to destabilize natural fine particulate matter suspended in water. This process in known as coagulation. … The addition of alum causes these particles and colloids to clump or gather together to form heavier particles which will settle under water.

ADDITION OF DISINFECTANT: Disinfection kills or removes diseases (pathogens) from drinking water, reducing health risks. You can disinfect water by adding chemicals, using heat, using ultraviolet (UV) radiation, filtration, alum, distillation, or using a combination of these methods.

Evaluation: The teacher asked questions on what has been taught.

1. practicalize

2. practical.



Simple Farm Tools or Instruments ( Pry 3 Second Term)