How to make a primitive water filter from sand/charcoal
  • 1. What is the primary purpose of a primitive water filter?
A) To remove sediment and impurities from water
B) To boil water
C) To change the taste of water
D) To add minerals to water
  • 2. What is typically the first layer in a sand/charcoal water filter?
A) Cloth
B) Fine sand
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 kill bacteria
D) To neutralize the water's pH
  • 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 slow down the water flow
D) To disinfect the water
  • 5. What is the role of fine sand in a water filter?
A) To add minerals to the water
B) To improve the taste of the water
C) To filter out even smaller particles than coarse sand
D) To make the water clearer
  • 6. What is the purpose of activated charcoal in a water filter?
A) To make the water colder
B) To add minerals to the water
C) To add carbonation 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) Makes the water acidic
C) Adds nutrients to the water
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 glass bottle
B) A wooden box
C) A plastic bottle or bucket
D) A metal pot
  • 10. How should the layers of a water filter be arranged?
A) Based on color
B) From coarsest to finest (gravel, coarse sand, fine sand, charcoal)
C) In a random order
D) From finest to coarsest
  • 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) 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) Adding salt to the water
B) Adding sugar to the water
C) Freezing the water
D) Boiling the water
  • 14. How often should a sand/charcoal water filter be replaced?
A) Once a decade
B) Never, it lasts indefinitely
C) Regularly, depending on water quality and usage
D) Once a year
  • 15. Which material is NOT typically used in a primitive water filter?
A) Gravel
B) Bleach
C) Charcoal
D) Sand
  • 16. What characteristic of charcoal makes it useful in water filtration?
A) Its color
B) Its porous structure
C) Its hardness
D) Its weight
  • 17. If you don't have commercially activated charcoal, what can you use?
A) Plastic pieces
B) Regular coal
C) Ashes from a fireplace
D) Charred wood or coconut shells
  • 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 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) Plastic wrap
B) Paper towels
C) Aluminum foil
D) Cloth or cotton
  • 20. Which of the following is NOT a benefit of using a primitive water filter?
A) Reduces turbidity
B) Removes some chemicals
C) Removes sediment
D) Removes all viruses
  • 21. What does 'turbidity' refer to in water quality?
A) Acidity
B) Temperature
C) Mineral content
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) Larger gravel allows for faster flow but filters less fine particles
B) Smaller gravel allows for faster flow
C) Gravel size doesn't affect filtration
D) Larger gravel filters finer particles
  • 24. What is the best way to clean the sand and gravel before using them in the filter?
A) Rinse thoroughly with clean water
B) Soak them in bleach
C) Boil them
D) Microwave them
  • 25. Why is it important to wet the filter materials before the first use?
A) To disinfect the materials
B) To activate the charcoal
C) To make the materials heavier
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 make the water completely safe to drink
B) It can handle any level of contamination
C) It may not remove all dangerous pathogens and toxins
D) It will always change the taste of the water
  • 27. What does 'potable' mean in the context of water?
A) Dirty
B) Safe to drink
C) Salty
D) Cloudy
  • 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 water testing kit
C) A microscope
D) A pH meter
  • 29. Where is the ideal location to collect water you plan to filter?
A) Downstream near a town
B) As far upstream from potential pollution sources as possible
C) From a stagnant puddle
D) Anywhere convenient
  • 30. How does the filter help remove protozoa?
A) By physically trapping them within the filter layers
B) It doesn't remove protozoa
C) By attracting them to the charcoal
D) By chemically killing them
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