How to build a solar still
  • 1. What is the primary purpose of a solar still?
A) To purify water using sunlight
B) To heat water for showers
C) To generate electricity
D) To cool water in hot climates
  • 2. What is the most common material used for the transparent cover of a solar still?
A) Wood
B) Glass or clear plastic sheeting
C) Aluminum foil
D) Cardboard
  • 3. What is the function of the collection trough in a solar still?
A) To provide structural support
B) To heat the contaminated water
C) To block sunlight
D) To collect the condensed water
  • 4. What color is most effective for the basin of a solar still to absorb heat?
A) Black
B) White
C) Silver
D) Clear
  • 5. What type of energy powers a solar still?
A) Mechanical energy
B) Electrical energy
C) Solar energy
D) Chemical energy
  • 6. What process causes the water to condense inside the solar still?
A) Chemical reaction
B) Filtration
C) Reverse osmosis
D) Evaporation and condensation
  • 7. What type of water should be used in a solar still?
A) Clean drinking water
B) Contaminated or brackish water
C) Distilled water
D) Deionized water
  • 8. Why is a tight seal important for a solar still?
A) To prevent water vapor from escaping
B) To reduce condensation
C) To attract more sunlight
D) To allow for ventilation
  • 9. What is the ideal angle for the transparent cover of a solar still in relation to the sun?
A) At a 45-degree angle
B) Parallel to the ground
C) Perpendicular to the sun's rays
D) Any angle is sufficient
  • 10. What safety precaution should be taken when using glass for a solar still?
A) Use a magnifying glass to focus sunlight
B) Handle with care to avoid breakage
C) Wear sunscreen
D) No precautions are necessary
  • 11. What increases the efficiency of a solar still?
A) Using cold water
B) A smaller surface area for evaporation
C) A larger surface area for evaporation
D) Using reflective materials inside the still
  • 12. Which material is suitable for the basin of a solar still?
A) Dark-colored plastic or metal
B) Clear glass
C) Mirrored surface
D) White cloth
  • 13. What is a common environmental benefit of using a solar still?
A) Reduced reliance on fossil fuels for water purification
B) Land degradation
C) Increased carbon emissions
D) Depletion of water resources
  • 14. What is the approximate yield of a simple solar still per day?
A) 10-20 liters per square meter
B) 50-100 liters per square meter
C) Less than 0.1 liter per square meter
D) 1-3 liters per square meter
  • 15. Why is it important to clean the inside of the transparent cover regularly?
A) To prevent algae growth
B) To collect more water
C) To maintain transparency and sunlight penetration
D) To increase humidity inside the still
  • 16. In what type of climate are solar stills most effective?
A) Polar climates
B) Cold and cloudy climates
C) Sunny and warm climates
D) Humid and rainy climates
  • 17. What type of impurities does a solar still effectively remove?
A) Salts, bacteria, and heavy metals
B) Viruses
C) Radioactive isotopes
D) Dissolved gases
  • 18. What is the function of the angle of the transparent cover?
A) Provides structural support to the still.
B) Reflects sunlight away from the still.
C) Facilitates the flow of condensed water to the collection trough.
D) Traps heat inside the still.
  • 19. Which of the following is NOT a key component of a basic solar still?
A) A water pump
B) A transparent cover
C) A basin
D) A collection trough
  • 20. What is the primary reason for using a dark-colored basin?
A) To absorb more solar radiation and heat up the water faster
B) To make the still more aesthetically pleasing
C) To prevent algae growth
D) To reflect sunlight and keep the water cool
  • 21. How does a solar still separate water from contaminants?
A) By chemically treating the water
B) By evaporating the water and leaving the contaminants behind
C) By boiling the water and collecting the steam
D) By filtering the water through a membrane
  • 22. What maintenance is required for a solar still?
A) No maintenance is required
B) Daily draining and refilling of the basin
C) Annual lubrication of moving parts
D) Regular cleaning and occasional replacement of the transparent cover
  • 23. Why is ventilation usually avoided in a simple solar still design?
A) To prevent water vapor from escaping and reduce condensation efficiency
B) To allow for temperature regulation
C) To prevent the buildup of pressure
D) Ventilation is always necessary for optimal performance.
  • 24. What is the relationship between the size of a solar still and its output?
A) Larger stills are less efficient due to heat loss
B) Size has no impact on output
C) Larger solar stills generally produce more purified water
D) Smaller solar stills are always more efficient
  • 25. How does ambient temperature affect the performance of a solar still?
A) Higher ambient temperatures generally increase the rate of evaporation
B) Lower ambient temperatures are always preferable
C) Higher temperatures always damage the components.
D) Ambient temperature has no effect on performance
  • 26. What is a potential drawback of using a solar still?
A) Relatively low output compared to other water purification methods
B) High operating costs
C) Risk of explosion
D) Complex construction requirements
  • 27. What factor dictates how much dirty water can be put inside the solar still to work effectively?
A) The size of the water container
B) The sun's strength
C) The air temperature
D) The water level shouldn't be too high, as this can reduce the surface area available for evaporation.
  • 28. Why should water collected from a solar still be stored properly?
A) To prevent recontamination
B) To improve its taste
C) To reduce its temperature
D) To increase its purity further
  • 29. What is the most important factor when choosing a location for a solar still?
A) Access to direct sunlight
B) Proximity to a water source
C) A level surface
D) Protection from wind
  • 30. What is a benefit of using plastic sheeting rather than glass for the transparent cover?
A) Plastic sheeting is generally more durable and less prone to breakage.
B) Plastic sheeting is more transparent than glass.
C) Plastic sheeting is a better insulator than glass.
D) Plastic sheeting is always cheaper than glass.
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