Students note their ideas and predictions concerning the task in their journals. Teams carry out their investigations and record observations in their journals. Provide paper towels for clean up. Dispose of rubber gloves when finished. Teams present their filters to the class.
Students discuss their investigations, proposing explanations and conclusions.
Compare the filtered water with the polluted water. Some polluting particles are removed when water is filtered. Students should be warned not to drink their filtered water. Harmful bacteria and viruses may survive filtering. These must be killed by either boiling the water or adding chemicals to it.