This unit in science we have been working on water filters. Throughout February we were working on designs and materials for water filters. We were also talking about rivers and water sources that are polluted in different ways, we also talked about how important clean water is for humans. For this science unit we also read a book called Saving Salila’s Turtle in our science groups. Saving Salila’s Turtle is a book where a girl named Salila who tries to save a turtle in the polluted Ganges river, later in the book she designs a filter to make the water clean for the turtle’s water tank.
Finally today we made our first water filter designed by ourselves. Our first design of a water filter had materials that consisted of two screens, sand and gravel, and a wipe. Our group wanted to use screens because they would get out all the big particles, we wanted sand and gravel because before we tested it out and it cleaned out the polluted water very well and we wanted the wipe because it’s holes are not visible to the naked eye, only the water could get through. We got scored on each of the final products. We got scored two to three for this design, its color looked the same as the graded example three, but it had no particles at all. Our first water filter design did quite well, but it was slow. It went drop by drop through the stopper, taking about two minutes to fill half a cup. I think it went through very slowly because of the sand and gravel, but I think it worked well because of the wipe that took all the dirty particles away, plus the sand and gravel also helped take away dirty particles. After that we added more gravel and sand to the first design, it lightened the color a tiny bit but did nothing else except for slow it down a tiny bit.
Our last design had materials that consisted of a cotton ball, one screen, sand and gravel, and a wipe. We decided to take out one screen because we didn’t really need it and it was broken, also we added the cotton ball because it would take the darkly colored contaminated water and suck some of it up but not too much too make the water lighter and take some particles out. We only put one cotton ball because it would suck up to much water. This design worked better than our first design, the process was much faster but the final product was only a bit better. I think it went faster because we took out one screen and added the cotton ball. There were also no materials in it but the color was lighter which must have gave us a good two! This was a very cool process and I learned that the wipe can take away a lot of dirty particles but soaks up a bit of water, and I also learned that it is hard from keeping some of the sand from going into the water. I also found out the screen’s holes are too big so it can only keep a few big particles out.