Unit 1 SAS #3-7 (pg. 23)

3. a. Indirect: No water is actually seen in the filter paper but water was used in the process of manufacturing it. 
    b. Direct: Water is used and in direct contact when moistening the gravel and sand
    c. Direct: Water is used to cool the distillation apparatus

4. To purify water means to make the water 100% pure. However, it is not possible to completely get rid of all of the minuscule substances in the water. Although water may not be 100% pure, it is still okay to drink (unless from somewhere where you know it is unhealthy water). 

5. a. Boil water
    b. Filtration pumps
    c. Sedimentation (when particles settle out of the fluid)

6. In the oil-water separation step of the foul water experiment, the first substance we removed was the top layer of the liquid, which was the oil. In the sand filtration step, any solid particles were removed from the liquid to get to the next step of cleaning the water. In the last step of the foul water experiment, we used the charcoal adsorption and filtration step to get rid of any substances that decrease the water's purity, leading us to a cleaner water. 

7. a. Seawater can not be converted to drinkable water because salt dissolves in water, making the salt inseparable from the water when using the foul water lab. 
    b. To purify salt water, you would have to use the process of desalination (removal of salt) or boiling the water can also remove salt.