| Salt
of the Earth
Materials
Needed
-Table
salt
-Water
-Glass bowl, 2 qt. (2 liter)
-Measuring cup: 1 cup (250 ml)
-Measuring spoon:1 tablespoon (15 ml) |
Try
This! Make Mini-Saltbeds
- Work in pairs, small groups, or individually, or set this up as a class
demonstration.
- Stir together in the bowl 1 cup of water and 4 tablespoons salt.
- Wait.
Allow the
bowl to sit undisturbed until all the water evaporates. This
may take 3 to 4 weeks.
- Make
predictions in science journals before and during the process
about what will happen.
- Connect. What can you see in the slideshow photos that corresponds to
what
happened
in your experiment? (For example, which photo shows where climbing
clumps of frosty salt were formed? It happened as water rose
up
the sides of the pond and the salt in the water crystallized
as the water quickly evaporated.)
Discussion/Journal
Questions
- Why
do you think crystals line the bottom of the bowl, while white
frosty deposits appear on the inner sides of the bowl?
- How
could you find out where the salt in your kitchen come from?
- How
do you think each of these factors helps make the Baja lagoons
so ideal for solar salt production?
- The
lagoons are isolated from the sea.
- The
lagoons receive very little rainfall and almost
no
freshwater runoff.
- The
winds are brisk and persistent.
- What
effects might the saltmaking operation have on the whales and
the sea birds that come to winter in the lagoons each year?
National
Science Education Standard:
Materials can exist in different states: solid, liquid,
and gas.
National
Geography Standard:
Understanding the
physical and human characteristics of places.
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