The wild drama of a volcanic eruption captures many children's interest and elicits their curiosity about how volcanoes work. Activities on volcanoes can fill a rainy afternoon or winter day while you simultaneously entertain and educate your kids. With hands-on activities, your child can explore the earth's layers, plate tectonics and lava. As he constructs models of various volcano types and creates chemical eruptions, he will come away with a greater appreciation of the geology of planet Earth.
Volcanoes occur as part of the natural movement of the earth’s layered core, mantle and crust. Your child can make a visual representation of the earth's layers with the added reward of an edible treat for her efforts. You and your budding scientist can mix up two contrasting colors of cake batter to make a cupcake model of the Earth. Fill each cup one-third full with one color batter. Place a nut or hard candy in the center as the core. Fill to two-thirds full with the second batter color to complete the mantle. Bake according to package directions and frost with a thin layer of frosting as the crust. Let cool and slice one cupcake in half to see the cross-section of the core, mantle and crust.
The thin layer of the Earth's crust moves in plates over the molten magma beneath. As the molten magma builds up pressure, it finds weak spots where it can break through the outer crust and a volcano forms as the hot liquid pushes up. Eventually the pressure becomes so great that it erupts with great force. With several colors of craft dough, your child can demonstrate how the pressure on the plates creates a volcano. Let him roll out four 4-inch by 30-inch flat sheets of homemade salt dough to one inch thickness in different colors and stack them one on another. Alternately, you may use heavy sheets of craft foam instead. Squeeze two opposite sides of the stack of sheets between two large books, boards or blocks and watch as the center buckles up and forms a mountain.
Not all lava is created alike. Some lava is thin and runny, while others are thick and pasty, and everything in between. Thick, viscous lava tends to erupt pyroclastically, shooting out giant plumes of pumice, cinder and ash, while thinner lava eruptions usually ooze out without so much drama and violence. Give your child several paper plates, a tablespoon and a variety of liquids such as molasses, honey, water, liquid soap, shampoo, vinegar, applesauce, fruit juice, milk, yogurt and tempera paint. Place a tablespoon of a different liquid on each plate and measure how far it spreads in one minute, five minutes and 10 minutes. Mix various amounts of sand into the same liquids and repeat the experiment. Place a cup of several liquids that include thin and thick liquids into separate jars. Blow into each with a straw. Observe the difference in the speed of the bubbles. Explain to your child that the thin lava releases its gas quickly, relieving the pressure and reducing the violence while thicker lava retains its gas longer allowing the pressure to build up violent eruptions.
Soda Pop Volcano
Volcanoes come in different shapes: bowl-shaped shield cones with gentle, sloping sides formed by basaltic lava flow; circular or oval cinder cones with a single vent made of lava fragments; steep-sided composite or stratovolcanoes are made of rocky layers of lava, ash and volcanic rock debris; and lava domes which are steep-sided mounds of lava near a volcanic vent. Look at pictures of real volcanoes of each type and let your child select which one to model. A two-liter pop bottle can represent the lava vent. Set it on a metal cookie tray or in a box lid to contain the mess. Have your child mold salt dough, craft dough or modeling clay around the bottle in the shape of his chosen volcano type. Let it dry for 24 to 48 hours. Paint the mountain with tempera paint and if desired, add in landscaping details such as rivers, trees and bushes. Your child can finish with the grand finale of an erupting volcano in a couple of different ways. One method is to fill the bottle three-quarters full of warm water, adding red or orange food color if desired to mimic the color of lava. Put in six drops of liquid dish soap for every two tablespoons of baking soda. Pour white vinegar into the bottle and watch the lava flow. The other method is to form the volcano around an unopened bottle of diet cola, leaving the neck and lid accessible. When your child is ready to set off the eruption, take the volcano outside, remove the lid, quickly drop in a whole roll of Mentos and witness the dramatic eruption of soda lava.