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Earth Science 3 – 7
Dried Out
Purpose To grow salt crystals.
Materials
1-cup (250-ml) measuring cup
tap water
2 tablespoons (30 ml) table salt
spoon
art brush
sheet of black construction paper
blow-dryer
Procedure
1.Fill the measuring cup one-fourth (63 ml) full with water.
2. Add the salt to the water in the cup.
3. Stir well. The solution will look cloudy and there will be a few
undissolved salt crystals in the bottom of the
cup.
4. Swish the bristles of the art brush around in the saltwater so that you get
a lot of saltwater on the brush.
5. Use the brush to cover the entire surface of the black paper with salt
water, rewetting the brush often.
6. Adult-Step Use the blow-dryer to dry the paper.
Clear, box-shaped crystals will be stuck to the paper.
So Now We Know
You can get salt out of saltwater by making the
water change into an invisible air- like material called gas. Water will
change into a gas when it's heated. The blow- dryer heated the saltwater until
the water was changed into a gas and was gone form the paper, and only the
salt was left.
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