Next you want to make the dough into a volcano:
- Fill the empty drink bottle most of the way full with hot tap water.
- Add a squirt of dishwashing detergent and some baking soda (~2 tablespoons). If desired, you can add a few drops of food coloring, too.
- Set the drink bottle in the center of a pan or deep dish.
- Press the dough around the bottle and shape it so that you get a 'volcano'.
- Be careful not to plug the opening of the bottle.
- You may wish to dribble some food coloring down the sides of your volcano. When the volcano erupts, the 'lava' will flow down the sides and will pick up the coloring.