Glue a 1-liter plastic drink bottle to the middle of an aluminum pie plate or cardboard base.
Flatten modeling clay into a circle and then drape the clay over the bottle. Position the center of the clay circle over the mouth of the bottle. Remove the clay above the bottle’s mouth, so the volcano has an open spout.
Shape the rest of the clay around the body of the bottle. Tug the clay gradually away from the bottle’s body as you approach the bottom. This will result in a steeper and more realistic volcano shape.
Add 3 tbsp. baking soda, 1/2 cup warm water and 1 tsp. liquid detergent to the interior bottle. Use a funnel to prevent a mess.
Mix 1/2 cup of vinegar with red food coloring in a separate bowl or cup.
Pour the vinegar until the volcano’s opening when you want to create an eruption. Carbon dioxide gas will seek to escape the volcano, forcing a foamy concoction to the surface.