Fourth graders have been learning all about volcanoes! They investigated how differences in lava types explain differences in the shape and eruption patterns among volcanoes. Prior to creating our volcanoes, students compared two different types of “lava” — thin and thick. They learned that shield volcanos are formed by thin, runny lava that flows easily and spreads out. This cools into a dark colored basalt rock. Cone volcanoes are formed by thick, pasty lava that cools into a pale, Felsite rock. Thick lava forms cone volcanoes. Cone volcanoes explode, while shield volcanoes do not. This is due to the bubbles that form in the lava. While bubbles can move easily through thin lava and escape, they get plugged up in thick lava and try to escape, but they get trapped at the top. The pressure continues to build until it is too great, causing the volcano to explode.
Question to Explore
How can we create a model of a volcanic eruption?
- Measuring cup
- 10 ml of dish soap
- 100 ml of cold water
- 400 ml of white vinegar
- Food coloring
- Baking soda slurry (fill a cup about ½ with baking soda, then fill the rest of the way with water)
- Empty bottle
- Paper, scissors, markers, and tape to create volcano drawing.
- To make your volcano, create a cone with a piece of paper and cut off the corners to make it a circle. Leave enough room at the top for a bottle to fit through.
- Create your volcano design using markers, crayons, or colored pencils.
- Tape your completed volcano around the bottle (leaving enough room to pour your ingredients in).
- Combine the vinegar, water, dish soap and 2 drops of food coloring into the empty soda bottle.
- Use a spoon to mix the baking soda slurry until it is all a liquid.
- Eruption time! … Pour the baking soda slurry into the soda bottle quickly and step back!