Volcano Demo Ideas for Chemistry/Geology
Retrieved 3/28/05 from
http://chemistry.miningco.com/cs/howtos/ht/buildavolcano.htm
How To Build a Volcano Okay, it's the kitchen equivalent of a volcano, not a real one. It's
cool all the same! It's also more or less non-toxic, which adds to its appeal.
Difficulty: Average
Time Required: 30 minutes
Here's How:
1. First make the 'cone' of the volcano. Mix 6 cups flour, 2 cups salt, 4 tablespoons cooking oil, and 2 cups of
water. The resulting mixture should be smooth and firm (more water may be added if needed).
2. Stand the soda bottle in the baking pan and mold the dough around it into a volcano shape. Don't cover the
hole or drop dough into it!
3. Fill the bottle most of the way full with warm water and a bit of red food color (can be done before sculpting
if you don't take so long that the water gets cold).
4. Add 6 drops of detergent to the bottle contents.
5. Add 2 tablespoons baking soda to the liquid.
6. Slowly pour vinegar into the bottle. Watch out - eruption time!
7. Chemistry is Cool :-)
Tips:
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The cool red lava is the result of a chemical reaction between the baking soda and vinegar.
In this reaction, carbon dioxide gas is produced, which is also present in real volcanos.
As the carbon dioxide gas is produced, pressure builds up inside the plastic bottle, until the gas
bubbles (thanks to the detergent) out of the 'volcano'.
Adding a bit of yellow food coloring too will result in a lovely lava red-orange!
What You Need:
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6 cups flour
2 cups salt
4 tablespoons cooking oil
warm water
plastic soda bottle
dishwashing detergent
food coloring
vinegar
baking dish or other pan
2 T baking soda
Retrieved 3/28/05 from
http://chemistry.about.com/cs/demonstrations/a/aa033003a.htm
How to Make the Classic Chemical Volcano
Ammonium Dichromate Reaction
Introduction
The eruption of an ammonium dichromate [(NH4)2Cr2O7] volcano is a classic chemistry demonstration. The
ammonium dichromate glows and emits sparks as it decomposes and produces copious amounts of green
chromium (III) oxide ash. This demonstration is simple to prepare and perform. The decomposition of
ammonium dichromate commences at 180°C, becoming self-sustaining at ~225°C. The oxidant (Cr6+) and
the reductant (N3-) are present in the same molecule.
(NH4)2Cr2O7 --> Cr2O3 + 4 H2O + N2
The procedure works well in both a lighted or darkened room.
Materials
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~20 grams of ammonium dichromate
sand tray or ceramic tile, for use in ventilation hood OR
5-liter round bottom flask and porcelain filtering funnel
gas burner (e.g., Bunsen) OR
butane lighter or match, for use with flammable liquid (e.g., ethanol, acetone)
Procedure
If you are using a hood:
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Make a pile (volcanic cone) or ammonium dichromate on a tile or tray of sand.
Use a gas burner to heat the tip of the pile until the reaction begins or dampen the tip of the cone
with a flammable liquid and light it with a lighter or match.
If you are not using a ventilation hood:
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Pour the ammonium dichromate into a large flask.
Cap the flask with a filtration funnel, which will prevent the majority of the chromium (III) oxide from
escaping.
Apply heat to the bottom of the flask until the reaction begins.
Notes
Chromium III and chromium VI, as well at its compounds, including ammonium dichromate, are known
carcinogens. Chromium will irritate the mucous membranes. Therefore, take care to perform this
demonstration in a well-ventilated area (preferably a ventilation hood) and avoid skin contact or inhalation of
the materials. Wear gloves and safety goggles when handling ammonium dichromate.