How to Build an Erupting Volcano Cross-Section

Updated February 21, 2017

See a model volcano explode from the inside. Make a cross section of a volcano with clear sides so you can watch the lava flow up the conduit, before it spills over the sides. This is an easy, exciting science project for elementary students. It would also make a fun, messy outdoor summer learning project. For the truly adventurous, erupting volcanoes make a fascinating centrepiece for a dinosaur-themed birthday party.

Pour 1 tbsp of baking soda into a 44.4ml. clear glass bottle with flat sides, such as an extract bottle.

Cover the top 3 inches of the bottle with a thin layer of grey modelling clay.

Use a plastic drinking straw to scrape a thin path through the clay down the centre of both flat sides of the bottle so you can see the glass. This will represent the conduit for the lava. Scraping both sides allows light to show through.

Place the bottle in the centre of the pie plate and add a layer of brown clay on each side of the bottle without covering the flat sides of the glass. The brown clay represents the Earth's crust. The clear glass opening at the bottom represents the magma chamber. You may colour it red with a marker washable marker, if desired.

Add grey clay to the sides of the bottle over the brown clay to represent the side of the volcano.

Mix a drop of food colouring into 2 tbsp.. of vinegar.

Pour the vinegar into the bottle to make the volcano erupt.


Label the parts of the volcano with small strips of paper held on with straight pins. Use a small funnel to help you pour the baking soda and vinegar into the bottle.


This project is messy. Protect your work surface.

Things You'll Need

  • 425gr. clear bottle with flat sides
  • Tablespoon
  • Baking soda
  • Gray modelling clay
  • Plastic drinking straw
  • Disposable pie plate
  • Brown modelling clay
  • Red washable marker (optional)
  • Liquid measuring cup
  • Vinegar
  • Red food colouring
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About the Author

Camela Bryan's first published article appeared in "Welcome Home" magazine in 1993. She wrote and published SAT preparation worksheets and is also a professional seamstress who has worked for a children's theater as a costume designer and in her own heirloom-sewing business. Bryan has a Bachelor of Science in chemical engineering from the University of Florida.