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