Place the empty bottle on the pie tin.
Build your volcano with modeling clay, using the empty bottle as a foundation for the structure of the volcano. Leave the opening at the top of the volcano.
Wait for the clay to dry.
Put 3 tablespoons of baking soda inside the volcano. Use the funnel to ensure that none spills.
Mix 3 drops of red food coloring with 1/2 cup vinegar. This step is optional. Making the "lava" red will make the volcano look more realistic.
Pour the vinegar into the mouth of the bottle, using the funnel to make sure none spills. Remove the funnel quickly.
Watch the "eruption" as the reaction between the baking soda and vinegar causes the volcano to bubble over.