Geological Pyrotechnics

For a natural fireworks display, I recommend visiting an active volcano at night, but from a safe distance! The awesome power of molten rock exploding from the ground is geological pyrotechnics at its best! And walking on a cooled lava flow, whether the ropy, smooth pahoehoe, or the rocky aa, is the closest I can imagine to visiting another planet. Of course, most of us don't live close enough to a volcano to take our students on a field trip. Plus, I’m sure that the permission slips would be really extensive! So, for the next best way to show your students the wonders of volcanism, try building models.

There are three types of volcanoes, shield, cinder cone, and composite. After we discuss the differences, my students work in small groups to research one of the types. They create a poster or PowerPoint presentation about an actual volcano of that type. I have them include information on both the geological characteristics of the volcano and its historical significance. Next, they build a model of their chosen volcano. During their class presentations, they share information on the volcanoes and then we go outside to simulate eruptions.

When my students build their models, they must make them the correct shape and proportion for the type of volcano they are representing. We usually use paper mache around soda bottles for the basic structure and then we cover the outside to simulate the external appearance of the actual volcano. I allow students to print pictures of their volcanoes to help them build a good replica. In addition to a physically exact model, the eruption of the volcano must also be similar to the real one. Shield volcanoes, such as those that make up the Hawaiian Islands, are low and broad and have lava flow eruptions. To simulate that, my students pre-fill the bottles inside of their model with baking soda. Then they add vinegar with red food coloring to make the model erupt. 

Cinder cone volcanoes are small and steep and are usually covered in loose rocky lava, such as the Paracutín volcano in Mexico. Students cover their cinder cone models with sand or small gravel and paint them black. Then we fill them with dry potting soil or ash and use a bicycle pump to cause the characteristic pyroclastic eruption. The composite volcano, however, is a student favorite. Its large steep sides are mountain-like, such as Mts. Saint Helens, Ranier, and Fuji. The composite volcano erupts quite violently at times, with both lava and pyroclastic flows. To simulate this, students build their composite volcanoes around bottles of diet cola. They sometimes add small rocks or gravel to the cola. When it’s time for the volcanoes to erupt, we add a few Mentos candies.  If you’ve never tried this, you'll know it creates an instantaneous chemical reaction that shoots gas and cola high into the air. Definitely do this one outside! 

We also view films of volcanoes and draw diagrams of their inner workings. We discuss hot spots, convergent plate boundaries, and other geological causes of volcanoes. You can also tie this in to rocks and minerals by looking at the differences of extrusive and intrusive igneous rocks and how volcanic activity forms both. Try these ideas and those below to help your students appreciate the wonders of volcanoes, even if they have never seen one for themselves.

Volcano Lessons and Activities:

Explosive Attitudes: Volcanoes  

Students examine three types of volcanoes and the reasons that they erupt so differently in this excellent earth science lesson. Emphasis is placed on comparing and contrasting volcano types using the Cascade Mountain range as a model.

Building a Volcano  

Students research volcanoes and then build one out of salt dough. Before the final step is completed, they find main ideas about volcanoes,  write sequential steps to building, and use correct grammar, to gain knowledge about them. There is a material list with resource links too.

Volcano! Is That a Volcano on Your Plate?  

Students investigate where volcanoes come from. In this volcano lesson, students watch videos, do Internet research, and participate in experiments to discover the cause of volcanoes.

Where in the World Is That Volcano?  

Students identify the Earth's major volcanoes. They locate major volcanoes on a world map. Then, in groups, they research how the volcano affects the region in which it is located.