Experiment #3  Salt Flats

Dasht-e Kavir in Iran	Great Salt Lake

Salt flats and pans can be found on most deserts.  They formed when large bodies of water repeatedly evaporated and left behind a residue of salt.  Some salt pans, like our own Great Salt Lake, still have water.  In other places, like the Dasht-e Kavir region of Iran, the ground is completely covered with a crust of salt.  Explain why salt flats and pans are truly lifeless.  Plants and crops can't grow in salt.

1. Have students get into groups of 5.

2. To see how a salt flat is formed, have each group stir 5 tablespoons of table salt into 2 cups of warm water.

3. Pour the solution into glass loaf pans.

4. Place the pans on a sunny windowsill.

5. Ask the groups to check the pan each day.  Have them use a ruler to find the water level each day.  Have them record their findings on a piece of paper.

6. Continue step 5 until all the water has evaporated.

7. Have the students transfer their findings onto a Spreadsheet and create a bar graph to compare each groups findings.

When all the water has evaporated, pass the pans around and ask:

                        Where did the water go?

                        What is the residue?  Allow them to touch and taste.

Start a discussion about evaporation.  When someone uses a blow-dryer on wet hair, what happens?  Which do you think would dry something faster:  heat, wind, or a combination of both?