Compare water purification methods:

1. Boiling water: Boiled water is heated to kill any germs in the water. This method uses a lot of electricity or firewood and does not remove soluble or insoluble pollutants.

2. Filtering water: Pouring water through a funnel and filter paper removes most of the insoluble pollutants, such as sand. But germs can pass through the filter paper. So can soluble pollutants such as salts and chemicals.

3. Settling water: Water that is allowed to settle will appear clean, but not all the insoluble pollutants will settle. Germs and soluble pollutants are not removed.

4. Chemical treatments: Chlorine or iodine can be added to water to kill germs, but these chemicals are expensive and can make the water taste awful.

Water purification is an essential process aimed at making water safe for consumption. Different methods of purification focus on removing various types of contaminants. Let's delve into some common water purification techniques:

Boiling Water: This is one of the simplest and most traditional methods used to kill germs, including bacteria and viruses, in water. Heating water to its boiling point (100°C or 212°F at sea level) destroys most pathogens. This method requires a significant amount of energy, either from electricity or firewood. However, boiling does not remove chemical contaminants or suspended solids, which means it may not address all types of pollution present in the water.
Filtering Water: Filtration involves passing water through a filter medium, such as filter paper or a specialized water filter. This process is effective at removing large particles and insoluble pollutants like sand and dirt. However, filter papers are typically unable to capture microorganisms and dissolved substances such as salts and chemicals. Advanced filtration systems, like those using activated carbon or reverse osmosis, may offer more comprehensive purification.
Settling Water: Settling relies on the natural process of sedimentation, where particulate matter sinks to the bottom after water is left undisturbed. While this can clear up water visually, not all particles will settle, and pathogens as well as soluble pollutants remain in the water. Settling is often combined with other purification methods to enhance water safety.
Chemical Treatments: Adding disinfectants such as chlorine or iodine is a method widely used to kill microorganisms in water. Chlorine is especially common in municipal water treatment systems. While effective, these chemicals can impart a taste or odor to the water and require careful handling and precise dosage to avoid harmful effects. Chemical treatments do not remove physical impurities or chemicals already dissolved in the water.

Each method has its strengths and limitations. Often, a combination of these methods is employed to ensure that water is purified effectively, providing a safe and clean supply.