Page 109 - Demo

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Properties of Liquids and Solids
107
Properties of Liquids and Solids— Demonstration Kits, continued
“Bouncing Ball” Distillation—
Demonstration Kit
By: Doug De La Matter, Retired
Madawaska Valley D.H.S, Barry’s Bay, ON
Phase changes, such as melting and evaporation, can be very “moving” events when molecules are the size of balls! A tub full of jumbo rubber balls is a perfect demonstration device for comparing the energy and motion of molecules in the solid, liquid and gas phases. What happens when the tub is shaken, gently at first, and then with more and more energy? Relate what happens to the balls to the changes that take place on a molecular level when a solid melts or a liquid evaporates. The “bouncing ball” demonstra- tion will help students visualize key elements of the kinetic–molecular theory—how close together the molecules are in a solid, liquid and gas, their relative motion; and the attractive forces between molecules. Isn’t it time you made the kinetic–molecular theory truly kinetic?
Concepts: Kinetic–molecular theory, phase changes.
Time Required: 20 minutes
Materials Provided: Clear plastic container with lid and 14 rubber balls, assorted colors.
See free video at flinnsci.com.
Cincinnati Form Franklin Flask—
Demonstration Kit
By: The Flinn Staff
The ultimate in discrepant events. Show students that you can boil water by cooling it! Fill the specially designed flask one-third full with water. Bring the water to a boil and then remove the flask from the heat. Place a rubber stopper fitted with a thermometer in the neck of the flask. Invert the flask in a support ring and add crushed ice to the concave bottom of the flask. The water now begins to rapidly boil again. As the boiling continues, the temperature steadily drops to within 15–20° of room temperature.
Concepts: Boiling, vapor pressure, evaporative cooling.
Time Required: 15 minutes
Materials Provided: Cincinnati form Franklin flask, 1-hole rubber stopper.
Note: A thermometer, ring stand, and 12-cm support ring with clamp are required and available separately.
Salting Out—Density Bottle Kit
By: The Flinn Staff
Two layers of beads are suspended in the middle of a
bottle. Give the bottle a shake and the beads move to opposite ends. The beads then slowly move back to the starting position. How does this happen? Two liquid layers of differing densities create an interface in the middle of the bottle. When the bottle is shaken, a homogenous liquid mixture of uniform density is formed and the apparent densities of the beads can be observed. The attention-getting display is sure to generate questions and gives you a great lead-in for lessons on density, polarity, and solubility. Teacher Demonstration Notes and student hand- outs are included. The bottle may be reused for years.
Concepts: Density, non-polar vs. polar, solutions, immiscibility
Time Required: 10 minutes
Materials Provided: Plastic bottle, isopropyl alcohol, sodium chloride, and pony beads.
PROPERTIES OF LIQUIDS AND SOLIDS—DEMONSTRATION KITS continued on next page.
“Bouncing Ball” Distillation—Demonstration Kit AP6888
Catalog No.
Description
Price/Each
AP6888
“Bouncing Ball” Distillation—Demonstration Kit
$41.50
Cincinnati Form Franklin Flask— Demonstration Kit AP6566
Catalog No.
Description
Price/Each
AP6566
Cincinnati Form Franklin Flask—Demonstration Kit
$92.45
Catalog No.
Description
Price/Each
AP7931
Salting Out—Density Bottle Kit
$28.10
Salting Out—Density Bottle Kit AP7931