Pirate science activities: saltwater into freshwater

Shiver me timbers! Teaching pirate science experiments is fun and exciting! Fresh water for a long ocean voyage is a precious commodity and making saltwater into freshwater is an important environmental topic. This is Part 4 of our pirate science activities: drop anchor and try invisible ink, make your own compass, and foil boats.

Teaching with a theme works well with organizing science lessons into stations. When you don’t have enough resources for every group of children to do the same lab, stations can be the solution. Using stations is also a great differentiation technique. See Part 1 for my tips for organizing station labs.

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Saltwater into freshwater instructions

• Pirates sail the seven seas! Begin by making your own seawater (if you don’t have ocean water available). Add 1 tbsp (15 cc) to 2 cups (500 ml) of water you will use for this experiment.
• You will need a nice sunny day. Place your bowl outside or in a very sunny window. Place the jar in the center of the bowl. Fill the bowl around the jar with your saltwater. Pour slowly and make sure the jar does not float. Make sure that no seawater goes in the jar. Make sure that the jar does not tip over. (You may need to put something heavy in the jar).
• Cover the pot with plastic wrap, making sure it is sealed very well around the edges of the bowl. Gently press down in the center of the wrap so it dips down. Do not push so hard that it breaks the plastic wrap. The dip should be over the mouth of the jar. Use large rubber bands to make sure the wrap is tight.
• Allow the sun to do its work for at least 4 hours. As the water evaporates from the saltwater, where will it go?
• Carefully remove the plastic wrap, allowing any water drops to fall into the jar. How much freshwater did you make?

What countries get their freshwater from desalination? Why is this necessary?

Note: I do not recommend doing this experiment by boiling the saltwater on the stove with foil instead of plastic wrap. You might not be able to see the saltwater boiling and you could set up a situation with too much pressure in the pot.

Supplies

• Plastic wrap
• bowl
• jar or small beaker, shorter than the bowl
• salt
• water
• large rubber bands
• paper or notebook for recording results, pen

What is the science?

Content: solubility, distillation, water cycle

Ocean water is 35,000 parts per million salt to water. This is a weight to volume measure, which translates to 133 g of NaCl (salt) per gallon of water. If you are able to get enough water to evaporate from your saltwater, you should begin to see salt in the bowl. When saltwater is heated by the sun, only water evaporates. On earth, water evaporates from the ocean and eventually falls to earth as rainwater.

Challenge question: Can you find how to calculate how many tablespoons are equivalent to 133g of salt?

Resource links

• http://water.usgs.gov/edu/drinkseawater.html
  • Shipping Science: Building a Boat That Can Saline water: Desalination from the US Geological Survey
•  http://www.instructables.com/id/How-to-de-salinate-seawater-when-stranded-on-a-des/
  • From Instructables, a fun simulation of a desert island
•  http://www.sciencebuddies.org/science-fair-projects/project_ideas/EnvEng_p022.shtml#procedure
  • Solar-powered water desalination from Science Buddies
• http://www.thehomeschoolmom.com/homeschool-lesson-plans/pirates-unit-study/
  • Pirates unit study from The Home School Mom
• http://howtosmile.org/blog/posts/avast-me-hearties%E2%80%94its-pirate-science
  • Avast me hearties from Lawrence Hall of Science
• http://www.hobsess.com/september-19-talk-like-a-pirate/#.Vkzc2t-rQ6g
  • September 19: Talk like a pirate from Hobsess blog
• http://inspiredbyfamilymag.com/2012/09/25/no-sew-captain-hook-costume-from-a-t-shirt/
  • Captain Hook costume from Inspired by Familia
• http://ncmaritimemuseums.com/beaufort/resources/blackbeard/
  • Blackbeard’s Queen Anne’s Revenge from NC Maritime Museums

Let’s talk story

Pirate scientists

Me mateys Kelly and Jen love swashbucklers as much as I do. This is the fourth in a series of science ideas for pirate theme we put together. Here’s some of our pirate inspiration: Treasure Island, Peter Pan, Pirates of Penzance, Pirates of the Carribean, The Pirate Queen, and Jake and the Neverland Pirates.

In North Carolina, Blackbeard be “our” pirate (other states claim the lad, too!) Along with science, you can tie pirates to social studies. Other famous pirates: Barbarossa, Thomas Cavendish, Sir Francis Drake, Charlotte de Berry, Sir Henry Morgan, Black Bart, Stede Bonnet, Captain Kidd, Anne Bonny, Mary Read, Jean Lafitte, and Grace O’Malley.

I’ll be looking for comments below, or contact me at lisa [at] thecasabouquet[dot]com.

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