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How to Make Salt Water Drinkable

based on 35 ratings
Author: Crystal Beran

Grade Level: 8th - 10th; Type: Physical Science

Objective:

To find out whether ocean water can be made safe to drink.

The purpose of this experiment is find out if salt can be removed from ocean water so that it is safe to drink.

Research Questions:

  • Why is salt water unsafe to drink.
  • How much water does a person need to drink each day?
  • Why do humans need water to survive?
  • What processes are used to make non potable water safe for drinking?

Fresh water is the most important thing a person needs to survive. It is possible to go weeks without food but only a few days without water will kill most healthy people. Though the earth is covered by 70% water, only 3% of that water is fresh. Water shortages affect many communities each year and some scientists speculate that there could be serious worldwide water shortages if the climate changes significantly. Finding a way to make ocean water drinkable would ensure that humans have all the fresh water for drinking and agriculture that they need.

Materials:

  • Water
  • A stove or a Bunsen burner
  • A glass distilling flask
  • A drinking glass
  • A 4 quart sauce pan
  • A large leaf from a non-toxic plant (banana, fig, or taro are good choices).

Ask your science teacher if you can borrow some of the science supplies you need for this experiment or if you can have access to the science lab. Alternatively, you could order supplies from a science catalogue. Many plant nurseries will have banana or taro plants and may be able to give you one of the leaves. You can also ask someone who works in a garden center which other leaves are from non-toxic plants.

Experimental Procedure:

  1. Collect about two liters of salt water from the ocean or you can make your own by adding 70 grams of table salt to 2 liters of fresh water.
  2. If you have collected water from the ocean, boil it for five minutes to kill the microscopic life in the water.
  3. Taste the salt water. It is not necessary to drink any of it. You may spit it out after tasting.
  4. Rate the saltiness of the water on a scale like the one below.
  5. Record observations on what the water smells like.
  6. Record observations on what the water looks like.
  7. Taste fresh water from a bottle. Rate the saltiness of the water.
  8. Record observations on what the water smells like.
  9. Record observations on what the water looks like.
  10. Place a quantity of the salt water in a glass distilling flask.
  11. Place a drinking glass in position to catch the distilled salt water as it cools.
  12. Boil the salt water until you have enough to taste.
  13. Taste the distilled salt water. It is not necessary to drink any of it. You may spit it out after tasting.
  14. Rate the saltiness of the water.
  15. Record observations on what the water smells like.
  16. Record observations on what the water looks like.
  17. Place a quantity of salt water into a 4 quart sauce pan.
  18. Hold the leaf above the sauce pan and angle it into a clean drinking glass.
  19. Boil the water, keeping the leaf above the steam and directing the droplets into the glass.
  20. Taste the distilled salt water. It is not necessary to drink any of it. You may spit it out after tasting.
  21. Rate the saltiness of the water.
  22. Record observations on what the water smells like.
  23. Record observations on what the water looks like.
 
 

Taste (saltiness)

Smell
Sight
salt water
 
 
 
fresh water
 
 
 

distilled salt water by flask

 
 
 

distilled salt water by leaf

 
 
 
 

Terms/Concepts: Salinity; Distillation; Drinking water

References:

http://www.brighthub.com/engineering/marine/articles/29189.aspx                                                                                                  
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