Week 4: April 24, 2015

This is the fourth meeting of group 4 laboratory period. It is established that the group needs to test three different materials, with 3 different volumes of materials, and 3 different volumes of water per material. So, there will be a total of 27 trials. The three different materials are charcoal, sand, and fabrics, say from a cut up T-shirt. The group continued to discuss the tangible building of the filter. The original idea that was proposed was it would be a two-way pump. However, after more discussion this is proving to be more difficult than assumed. So, the group is discussing a new possible design in which the two-way pump can still work. Also, outside of class, a simple "protoype" design idea was built with a plastic tumbler bottle. Three holes were cut out on the bottom of the bottle, and the top was cut and rounded off. Using cardboard, a round surface was built and three wooden dowels in the shape of a tripod were attached to it using glue. In the real filter, glue will not be used, however this was used just for current circumstances to test the shape of this pump. Black cotton (t-shirt) material was wrapped around the cardboard and duct tape was taped underneath (just for current circumstances). Smaller holes were poked into the cardboard area. Pictures follow this blog post. Also during this laboratory period, sacs of charcoal were made with t-shirt fabric being the sac carrier material. These sacs were placed inside the clear plastic bottle. However, a problem arose because some fine charcoal was coming through the t-shirt. A proposed idea was to place sand under the charcoal as a second layer so that no charcoal would leave the holes. However, the group is in process of acquiring sand. The general idea of this test is to test the pressure of the the water and pump onto these charcoal sacs. This was tested, and pictures follow. However, the test did not work very well. There were too many holes poked into the cardboard pump, and too much charcoal was flowing through, and the water was darker due the charcoal. This will be tested again outside of class in the following week.