Build a Volcano!

What You Need:

• 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

What to do:

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!

Tips:

1. The cool red lava is the result of a chemical reaction between the baking soda and vinegar.
2. In this reaction, carbon dioxide gas is produced, which is also present in real volcanoes.
3. 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'.

http://chemistry.about.com/cs/ht.htm