How to make a primitive water filter from sand/charcoal
  • 1. What is the primary purpose of a primitive water filter?
A) To add minerals to water
B) To remove sediment and impurities from water
C) To boil water
D) To change the taste of water
  • 2. What is typically the first layer in a sand/charcoal water filter?
A) Fine sand
B) Cloth
C) Charcoal
D) Gravel
  • 3. What is the function of the gravel layer?
A) To add minerals to the water
B) To filter out large particles
C) To neutralize the water's pH
D) To kill bacteria
  • 4. Why is coarse sand used in a water filter?
A) To filter out smaller particles than gravel
B) To add flavor to the water
C) To disinfect the water
D) To slow down the water flow
  • 5. What is the role of fine sand in a water filter?
A) To add minerals to the water
B) To make the water clearer
C) To improve the taste of the water
D) To filter out even smaller particles than coarse sand
  • 6. What is the purpose of activated charcoal in a water filter?
A) To absorb chemicals and impurities
B) To add carbonation to the water
C) To make the water colder
D) To add minerals to the water
  • 7. What is the benefit of using activated charcoal?
A) Changes the water's color
B) Removes odors and some pollutants
C) Makes the water acidic
D) Adds nutrients to the water
  • 8. Why is it important to use clean sand and gravel?
A) To make the filter look nicer
B) To increase the water flow rate
C) To make the filter heavier
D) To prevent contamination of the filtered water
  • 9. What is a common container to build a primitive water filter in?
A) A wooden box
B) A metal pot
C) A glass bottle
D) A plastic bottle or bucket
  • 10. How should the layers of a water filter be arranged?
A) Based on color
B) From finest to coarsest
C) From coarsest to finest (gravel, coarse sand, fine sand, charcoal)
D) In a random order
  • 11. What should you do with the first batch of water filtered through a new filter?
A) Save it for later
B) Use it for cooking
C) Drink it immediately
D) Discard it
  • 12. Does a sand/charcoal filter remove all pathogens?
A) It only removes large parasites
B) Yes, it makes water completely sterile
C) No, it primarily removes sediment and some chemicals
D) Yes, it removes all bacteria and viruses
  • 13. What is a recommended additional step to ensure water safety after filtering?
A) Freezing the water
B) Adding sugar to the water
C) Adding salt to the water
D) Boiling the water
  • 14. How often should a sand/charcoal water filter be replaced?
A) Once a decade
B) Regularly, depending on water quality and usage
C) Once a year
D) Never, it lasts indefinitely
  • 15. Which material is NOT typically used in a primitive water filter?
A) Charcoal
B) Gravel
C) Bleach
D) Sand
  • 16. What characteristic of charcoal makes it useful in water filtration?
A) Its color
B) Its weight
C) Its porous structure
D) Its hardness
  • 17. If you don't have commercially activated charcoal, what can you use?
A) Regular coal
B) Ashes from a fireplace
C) Plastic pieces
D) Charred wood or coconut shells
  • 18. Why is it important to avoid using chemically treated wood charcoal?
A) It won't filter the water effectively
B) It will clog the filter
C) It can leach harmful chemicals into the water
D) It will make the water taste bad
  • 19. What can be used to pre-filter the water before it enters the main filter?
A) Cloth or cotton
B) Aluminum foil
C) Plastic wrap
D) Paper towels
  • 20. Which of the following is NOT a benefit of using a primitive water filter?
A) Reduces turbidity
B) Removes some chemicals
C) Removes all viruses
D) Removes sediment
  • 21. What does 'turbidity' refer to in water quality?
A) Mineral content
B) Acidity
C) Temperature
D) Cloudiness or haziness
  • 22. What can you do to improve the flow rate of a slow filter?
A) Compress the layers more tightly
B) Add sugar to the water
C) Clean or replace the filter layers
D) Add more layers
  • 23. How does the size of the gravel affect the filtration process?
A) Gravel size doesn't affect filtration
B) Larger gravel filters finer particles
C) Smaller gravel allows for faster flow
D) Larger gravel allows for faster flow but filters less fine particles
  • 24. What is the best way to clean the sand and gravel before using them in the filter?
A) Soak them in bleach
B) Boil them
C) Microwave them
D) Rinse thoroughly with clean water
  • 25. Why is it important to wet the filter materials before the first use?
A) To activate the charcoal
B) To make the materials heavier
C) To remove air pockets and allow for even water flow
D) To disinfect the materials
  • 26. What is a limitation of using a sand and charcoal filter in treating heavily polluted water sources?
A) It may not remove all dangerous pathogens and toxins
B) It can handle any level of contamination
C) It will always make the water completely safe to drink
D) It will always change the taste of the water
  • 27. What does 'potable' mean in the context of water?
A) Dirty
B) Salty
C) Safe to drink
D) Cloudy
  • 28. Which of the following is an essential tool for building a basic water filter?
A) A water testing kit
B) A pH meter
C) A microscope
D) A container with a hole for drainage
  • 29. Where is the ideal location to collect water you plan to filter?
A) Anywhere convenient
B) Downstream near a town
C) From a stagnant puddle
D) As far upstream from potential pollution sources as possible
  • 30. How does the filter help remove protozoa?
A) By attracting them to the charcoal
B) By physically trapping them within the filter layers
C) By chemically killing them
D) It doesn't remove protozoa
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