On Wednesday February 3, 2021, Form 3 CCP Science students at St. Margaret College Secondary School, Verdala, Cospicua learned about the process of filtration and how to make a water filter at home as part of their Science practicum. This Science task was related to their Science study unit about Filtration and Separating Mixtures.
After learning the science concept of solubility and insolubility, students were given the task of learning how to separate sand from water through a simple filtration experiment. Then students were encouraged to build a simple water filter at home as part of the ‘Saving the Drop Campaign’. It doesn’t take long to build a simple water filter at home and students were encouraged to opt for recycling material in this science task.
To build a water filter at home one needs the following materials: plastic bottle, tall drinking glass, small stones or gravel, clean sand, activated charcoal, cotton balls or cloth and scissors or knife.
Then one has to follow some simple steps to build a basic water filter. First, one cuts the bottom of the plastic bottle using scissors or knife and place it upside down into the tall drinking glass. The first thing to put inside the plastic bottle is cotton balls or cloth, making a two inch thick layer. Then one adds an inch of activated charcoal as the second layer on top of the cotton layer. As third layer, one adds about two inches of small stones or gravel and then as fourth layer, another four inches of clean sand on top of the gravel. The final layer should be another layer of gravel while leaving a half-inch space from the top of the upside down bottle. Then first tests can be done by pouring some muddy water in the water filter and observing the filtered water dripping down clean into the glass below. It is important to avoid drinking the filtered water unless it is boiled.
For this experiment, students were instructed to test the water before and after the filtration process. Several water filters can also be made using different materials to observe which materials better filter muddy or dirty water into clean water.
The materials used to build a water filter at home can easily be found and it is very important that recycled material is used for this science project. Instead of cotton balls or cloth, a coffee filter can be used and instead of gravel, small pebbles would do just as well.
Each layer of the water filter has a purpose. Large sediments (like leaves or insects) in water are filtered while going through the small stones or gravel, whereas fine impurities are removed by the sand layer. Finally, contaminants and other impurities are removed by the activated charcoal through chemical absorption.
Senior Science teacher, Martin Azzopardi sdc (who supervised this experiment) said: “Teaching Science students how to build a water filter at home is a very simple science task which helps them understand the need to save every drop of water at home and put science into practice.”
Mother Earth filters water naturally as it is absorbed into the aquifers of the ground. Ground soil filters water from leaves, insects and other debris as part of the water cycle infiltration process. Unfortunately, ground water is being contaminated due to pollution such as household chemicals/products and fertilizers and so it becomes unsafe to drink.
Thanks to this science project, students learn how the process of infiltration works and are encouraged to save water consumption. This project aims to reach three of the United Nations Sustainable Development Goals: Responsible Consumption and Production, Climate Action, and Quality Education.