Ghost Crystals - Light & Water
Grades 1-4
Have you ever tried making Ghost Crystals with your students?
Materials Needed: ghost crystals,
jar, string. Optional: computer and printer.
Let your children look carefully at a jar that appears
to contain only water with a small noose (string) hanging down into it.
Show the children that when the string is lifted out of the jar, a large
shiny crystal is found to be tied up in the noose. When the string is lowered
back into the water, the crystal again becomes invisible!
This is a great way to stimulate discussion with your
young students about why the crystals cannot be seen in the water. They
will also have a wonderful time demonstrating the experiment to their parents.
Notes:
- Be sure to set standards for this experiments as you
do for all work with science. Let the children know that the crystals are
NOT for tasting or eating. (One student, for example, said she was going
to fool her father and put them into his glass of water.) It's best that
children learn from an early age that they must follow the rules for science
experimentation.
- These crystals are very similar to those added to potting
soil and cut flowers to keep them from drying out. The crystals appear
to disappear in water because they are made up almost entirely of water.
They essentially "look" like water, and light will pass from
the surrounding water into the crystal without being refracted at all.
Ghost Crystals can be ordered from Flinn Scientific, Inc.,
P.O. Box 219, Batavia, Illinois 60510, (800/452-1261).
An excellent book for children about crystals and crystal
making is Snowflakes, Sugar, and Salt / Crystals Up Close
by Chu Maki, Lerner Publications Company, 1993.
Computer application: You may wish to have your children
describe this experiment and what they learned by using the computer. They
might draw pictures for parents and friends about their new discovery-ghost
crystals! They might think of other ideas for using ghost crystals and
write these ideas using a word processor.
Suggestions for Parents:
If you'd like to do this experiment with your children, set up your rules
for science studies at home. For this investigation, children should know
that they must not taste the crystals or try to fool anyone else into tasting
them. You might ask the children to prepare this experiment to show to
grandparents. They'll need to set the experiment up, carry it out, and
then explain why the crystals can't be seen. If your child's school does
not do this experiment, your child might do it for the class.
Submitted by:
Celeste Bunting
Grade 1 Teacher
Worcester Country School, Berlin, MD
Lesson Plan Disclaimer
