Day #2 Homework: Semester 1

A.8 Questions 1-4 pg. 22

1. List three water uses you could do without.
     1. Washing a pet.
     2. Washing a car
     3. Watering plants.

2. Identify one activity that you could not do without. 
- Drinking/consuming water.

3. For which tasks could you reduce your water use? How?
- Taking shorter showers allows someone to save more water by not using the water for a extra long amount of time.

4. Impurities added by using water for one particular use may not prevent its reuse for other purposes. For example, you might decide to save hand-washing water and use it later to bathe your dog.
A. For which activities could you use such impure water?
- Bathing, watering plants, or washing hands
B. From which prior uses could this water be taken?
- Car washing, window washing, dishwashing 

Both direct and indirect uses of water must be considered when evaluating water use.

3. The following are 3 water uses associated with your foul-water laboratory investigation. Classify each as either a direct or an indirect water use. Explain your answers.
A. Manufacturing filter paper
- Indirect because it is a hidden use of water.
B. Premoistening of the sand and gravel
- Direct because it is an obvious use of water.
C. Use of water to cool the distillation apparatus.
- Indirect because it is a hidden use of water.

4. What does it mean to "purify" water?
- Clean up dirty water to make it as clean as possible. 

5. Identify at least three techniques for purifying water.
- Oil-water separation, sand filtration, charcoal adsorption and filtration.

6. What was removed from your foul water sample in each step of of that investigation?
- A layer of oil. 

7. The procedure used in the foul water lab. could not convert seawater to water suitable for drinking.
A. Why not?
- It would take too long. Plus our experiment was to make water suitable for hand washing.
B. What additional purification steps would be needed to make seawater suitable for drinking?
- Desalination: the removal of salt from seawater. 
- Distillation: purifying a liquid by vaporizing it.