1. Why does it matter?

2.  Are you concerned about the quality of the water coming out of your faucet?  Do you ever really think about water quality?  According to the Environmental Protection Agency, more than 90% of the water supply in the United States is safe to drink.

3.  This is not the case in many countries around the world.  South America, Central America, India, Africa, and parts of Asia all have a large percent of their population with no access to safe water.  The map below shows the percentage of population with access to safe water by country.

4.  What might cause water to be unsafe to drink?  Are there some countries that are more susceptible to pollution than others?  Why?

5.  How do you think a filter works?  On a very basic level, the process of filtration involves the flow of water through a granular bed of sand, or another suitable material such as gravel or rocks, at a low speed.  The filtration materials retain most solid matter while allowing the water to pass.  This is usually repeated through several layers.

6.  What are some ways you can think of?  Which of these uses would require the water to have gone through some type of filtration?  Which use do you think requires the highest level of purity?  Human consumption  Washing clothes or dishes  Bathing  In a garden  Washing a car  For industrial use  For medical use Think about ways water is used on a daily basis.

7.  Reflect for a moment on what you have learned about physical properties.  Which of the physical properties are important to consider?  Physical properties include, but are not limited to: color, size, shape, texture, density, flexibility, conductivity, magnetism, opacity, mass, odor, melting point, boiling point, solubility, polarity, and state.

8.  Your team will be working cooperatively, collaborating to design and test a water filtration system.  You will use your knowledge of science and math with your creativity to design a water filtration system that can clean contaminated water by removing particulate matter and color. It also needs to filter the water in a reasonable amount of time.