Volcano Project

Problem

How can you make a model of an erupting volcano?

Materials

• 16-oz (480-ml) soda bottle
• Large baking pan
• 2 measuring cups (250-ml)
• 1 tablespoon (15 ml) flour
• 1 tablespoon (15 ml) baking soda
• Spoon
• Funnel
• Red food coloring
• 1 cup (250 ml) white vinegar
• Tap water

Procedure

1. Place the soda bottle in the pan.
2. In one of the measuring cups, mix together the flour and baking soda.
3. Pour the flour and baking soda mixture through the funnel into the soda bottle.
4. Add 20 drops of red food coloring to the bottle.
5. Pour about one half of the vinegar in to the bottle.
6. When the foaming stops, pour the remaining vinegar into the bottle.

Results

Red foam bubbles out the top and then runs down the side of the bottle.

Why?

The baking soda reacts with the vinegar, producing carbon dioxide gas. As the gas forms, it expands quickly, pushing the liquid and the flour particles out the top of the bottle. The mixture of the gas, flour, red food coloring, and liquid produces the foam, which simulates the foamy magma in an active volcanic eruption.

LET'S EXPLORE

1. Does the amount of vinegar affect the results? Repeat the experiment three times: first, using ¹/₄ cup (63 ml) of vinegar and adding enough water to fill the measuring cup; second, using ¹/₂ cup (125 ml) of vinegar and filling with water; and finally, using ³/₄ cup (188 ml) of vinegar and filling with water. Science Fair Hint: Photographs can be used to represent the results.
2. Does the amount of baking soda affect the results? Repeat the original experiment twice, first using 1¹/₂ teaspoons (7.5 ml) of baking soda, and then using 2 tablespoons (30 ml) of baking soda.
3. Does the flour affect the results? Repeat the original experiment, this time omitting the flour.

SHOW TIME!

1. A volcano is a mound of rocky materials formed around a hole through which molten rock and gases are, or have been, expelled from within the earth. Build a working simulated model of a volcano by placing a soda bottle in a large pan and shaping moist soil around the bottle to form a mountain. Repeat the original experiment to simulate a volcanic eruption.
2. A more lasting model can be made by molding thin window-screen wire around the bottle, in the shape of a mountain. Mix plaster of paris by following the instructions on the box, and cover the wire with the plaster. Allow some of the plaster to flow down from the mouth of the bottle to represent the flow of lava Oiquid rock on the surface of the earth). Allow the plaster to dry, then paint it. When the paint has dried, repeat the original experiment to simulate a volcanic eruption.

CHECK IT OUT!

Volcano cones form when lava and rock from erupting volcanoes pile up on the earth's surface. Use an earth science book to find out more about the shape of these cones. Draw diagrams and/or make cross-section clay models to represent the different volcano cones, such as the shield cone, composite cone, and cinder cone.

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Janice VanCleave's Volcanoes
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