Group Title: Environmental teaching plans
Title: Collecting salt
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 Material Information
Title: Collecting salt
Series Title: Environmental teaching plans
Physical Description: Archival
Language: English
Creator: St. Croix Environmental Education Team
Publisher: Division of Fish and Wildlife
Place of Publication: Frederiksted, VI
 Record Information
Bibliographic ID: CA01300920
Volume ID: VID00015
Source Institution: University of the Virgin Islands
Holding Location: University of the Virgin Islands
Rights Management: All rights reserved by the source institution and holding location.


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Author: Leslie Repp, Eulalie P. Rivera
Grade Level: K-3

Concepts: Disciplines:
1. The Sun 1. Science
4. Clean Water 2. Social Studies
6. Natural Resources 3. Mathematics

Students shall demonstrate, by weighing and recording, the daily loss of seawater to
evaporation over a period of a week and that the salt crystals in the residue are cube shaped.

Collecting salt by evaporation has been practiced in many lands bordering the seas for
centuries. Salt was used to preserve food before the widespread use of refrigeration. Long ago
ponds on our islands functioned to provide salt to their communities.

Materials Needed:
Shallow container (aluminum pie or cake pan) for salt water, scale, microscope or hand lens.

Ask a student to bring sea water in a quart plastic container to class. Place the water in a
shallow container such as in aluminum pan provided by bakeries. Use a scale to record the
initial weight of the water and container. Place the pan with the water in a window or area
exposed to sunlight, keeping it in the same area until all the water is evaporated. On the
Experimental Record Form each day record the weight of the water and container and deter-
mine how much evaporation took place. When all the water has evaporated, examine the salt
crystals that remain. NOTE: Additional activity on work sheet.

Discussion Questions.
What is evaporation? What causes it? Where does the water go? What is left when seawater
has evaporated?

How was pond salt collected on the islands long ago? (By picking the crystals out of the water
by hand, during a dry spell).

Why is pond salt desirable? (For the trace elements it contains).

What happened to the islands salt ponds? (Only one on St. John is still functioning).


1. Date Experiment Began:

2. Weight of seawater and container:
3. Daily evaporating record:

Weight of Water
And Container


A. Day I

B. Day 2

C. Day 3

D. Day 4

E. Day 5

4. Date all water evaporated?

5. A. What remained in the bottom of the pan?
7. B. What is the weight of the residue?
C. Look with a hand lens at the residue. What is the shape of the crystals left in the pan?

A comparative experiment could be done by placing another seawater container, similar in
weight, in a place not exposed to sunlight and record the length of time. This would
demonstrate the evaporative power of the sun.


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