Place a paper cup in the middle of a large cookie sheet. Wrap the outside of the cup with aluminum foil to resemble the shape of a volcano.
Roll some clay into a large circle, just like making a pie crust. Lay the clay over the cup and foil. Cut out the center of the clay and wrap the edges of the clay around the lip of the cup. Shape the play to look like a mountainside.
Place 3 tsp. baking soda inside the volcano. When you're ready to make your volcano erupt, pour 1 cup white vinegar over the baking soda.
Tape a small paper cup or plastic bottle to a large piece of cardboard. Place the cardboard on a cookie sheet.
Crumple up several sheets of newspaper and tape them around the cup or bottle to make the volcano shape. Cover the newspaper with foil and tape in place.
Mix two parts water with one part flour to make a thin paste. Dip strips of newspaper into the paste and lay then over the foil. Layer three layers of newspaper over the foil and allow to dry overnight.
Paint the volcano with acrylic paints to look realistic.
Put 3 tsp. baking soda into the cup. Add a few drops of dish soap to make the eruption even more foamy. Pour in 1 cup vinegar to make the volcano erupt.
Build a volcano body that will fit over the top of a 20-ounce bottle of soda. Make the body of the volcano from insulating foam found at hardware stores. Cut a hole large enough for the base of the bottle into a 18-by-18-inch piece of cardboard. Place the bottle in the hole. Spray insulating foam in a circle around the bottle to make the volcano shape. Make the base of the volcano the widest point, and gradually narrow the width of the insulation as you near the top of the bottle.
Allow the foam to dry for 24 hours, then paint with acrylic paint and seal with clear acrylic sealer.
Place the volcano over an opened 20-ounce bottle of cola soda. Drop in two or three Mentos and watch the volcano explode.
Bend a piece of posterboard into a cone shape with a flat bottom. Cut off the top of the volcano so it can fit over the top of a 20-ounce soda bottle. Place the volcano over the soda bottle.
Fill in the space around the bottle with newspaper. Tape the volcano to a cookie sheet or other container. Paint the volcano with acrylic paints to look like a real mountain or volcano.
Add 2 tbsp. baking soda and four drops of liquid soap to the bottle. Add 1 cup vinegar to make the volcano explode.