Do you use filters? If you answered no, chances are that you are wrong. Filters are everywhere, from coffee filters to water filters. Filters help remove nasty particles, twigs and leaves from any liquids or gasses. An extraordinary thing about engineering is that it helps humans address problems by designing and developing solutions. Human beings need water to survive. In some areas of the world, water is either scarce, polluted or both. Engineering is a science which can be applied to design water filters to clean water.
To begin the science unit we were read a book called Salila. It was about a river in India called Ganga Ma [Ganges River]. It was polluted by bacteria so people who drank from it got sick. One day when Salila was walking home from school she noticed a frog that had been sickened by the oil in the water. She noticed the rainbow sheen of the oil sitting on the water. This made Salila want to design a water filter and to stop the pollution in the river.
Our job was to filter out dirt, tea leaves and cornstarch. We were given these materials: sand, gravel, cotton balls, screens, paper filters, filters holders, and 2 containers. After that we set to work, designing filters. Some people used only screens, others used all of the materials. To measure the cleanliness of the water from each of our tests we had a rating scale. Our rating scale was comprised of 5 bottles, numbered 1-5, 1 being the dirtiest, 5 being the cleanest (tap water). We all had to use a filter holder, (which is half of a soda bottle with a cap with a hole the diameter of a pencil drilled through it) to hold the different materials used when testing our filters. Then we tested them.
We collected 2 cups, 1 for dumping the dirty water into the filter and second to collect the clean or dirty water coming from the filter. Then we started testing the filters by pouring dirty water into the top of the filter. This went through our filter contraption. The filter either cleaned out the major particles or changed the color to look healthier. Some filters got 4’s, some were 3’s and almost none were 2’s. Rarely ever 1’s. Some of the groups had screens on top and cotton balls on the bottom, others had unrolled cotton balls on top and screens scrunched up in the neck. Dr. Reinemann was our mentor making suggestions. Every group had different colored water.
Finally, they came up with some ideas for trying to sell their filter. Dr. Reinemann did 3 example presentations. One where she was like a hippy, another where she was really silent and scared-looking and third where she talked nice and clear and had a good descriptive poster.
First we made a “Brain Frame” (a graphic organizer) and filled it in with ideas. Then we made a rough draft for our poster. The poster was an assessment, which included a picture, good features and an explanation about the filter to convince people to buy your filter and a business card to take home. Some of the groups names were “Olympus Water Filters” or ” Epic Water Filters”. Some of the groups were convincing in their presentation. Others were awesome in their speech. Some people acted as if it were a commercial. Others just thought it would be fine to do a normal presentation. At the end of each presentation, each group went up to Dr. Reinemann and gave her their group business card.
As engineers, we used the Engineering Design Process in developing our water filter. The first step was “Ask”, in which we asked how to make the best filter. The next step was to “Imagine” what materials would be needed and what the contraption would look like. “Plan” the order for the materials within the filter. The fourth step was to “Create” the filter we had imagined. The final step was to “Improve” the filter we had created in the areas that could be improved.
Now, can you imagine a world without engineers to design water filters?
Reported by Michelangelo, Indy, Calden