Drought Mitigation Trade-offs

What are the trade-offs for mitigating drought through desalinization of sea water?

Seawater on the coast of Maui. Photo courtesy of L. Dahlman.

Explore the positive and negative aspects of desalinization of seawater as a source of freshwater? The following links can provide a starting point for your research.

• Why it's so hard to make salt water drinkable
• Desalination Breakthrough: Saving the Sea from Salt
• One of the driest countries on Earth now makes more freshwater than it needs
• Watch this brief video on desalination and how it's currently being used in California.
  
  

Hands-on Activity

Distill a sample of salt water to produce freshwater.

1. Gather these materials:
   • 400 mL beaker with 200 mL tap water plus 7 g salt
   • hot plate
   • ring stand
   • glass funnel
   • clamp
   • one-hole stopper with bent glass tube
   • rubber tubing
   • 200 mL beaker
   • watch glass
2. Put a drop of the saltwater on the watch glass and set it in a warm place to evaporate. Examine the residue left behind on the watch glass after the water evaporates.
3. Assemble the lab equipment as shown.
4. Turn hot plate on and bring salt water to a gentle boil.
5. Test the final product for solute by putting a drop on the watch plate and letting it evaporate. After the water has evaporated, check that spot for any residue.
6. Examine the container that held the original sample.