Homeschool 101: Lemon Volcano Experiment

Since becoming a homeschool parent last fall, I decided I needed to make sure my boys still participated in STEM activities. Upping my science experiment game (which was non-existent before), was something I wanted to push myself with. It helps that I have a sister who has gone to school for Nuclear Medical Physics and always has suggestions for experiments.

This last week, I wanted to talk to the amigos about acids and bases. They have done the Mentos in Coke before and they have built multiple volcanoes with my mom; but we’ve never talked in-depth about the chemical reactions between acids and bases, the pH scale, and why not all acids and bases react together. I thought it would be fun to do a less messy, more controlled volcano. Thus the lemon volcano was born.

If you are not familiar with the pH scale, or it’s been a while since high school; it goes from 0-14 with 0 being the most acidic and 14 the most alkaline (or a base). The closer to the end of each side the more it will react with its counterpart. Lemons are a 2 on the acid side and baking soda is a 9. They react well together. Now, dish soap is also alkaline or a base. But why didn’t it react with the lemon juice? Well, most dish soap is closer to a neutral, between a 7-8. The closer a substance is to a neutral, the less of a reaction will occur. You can generally tell an acid is an acid because it draws the moisture out of your skin and causes a dry feeling (not all acids should be handled with bare hands), and alkaline substances have a slippery feeling (again, not all bases or alkaline substances should be handled with bare hands).

Sometimes acids will react with acids and bases will react with bases, so be careful when conducting experiences. One example is that if bleach and ammonia are combined they create a toxic fume called chloramine. Have you ever heard not to use bleach with Windex while cleaning? That’s why. Windex usually has ammonia, but thankfully it is much easier to find ammonia-free glass cleaner these days. I’d recommend researching the acids and bases before you do any combining so a negative reaction doesn’t occur.

Lemon Volcano Experiment


  • baking sheet
  • paper towels
  • sharp knife
  • kitchen knife or wooden popsicle sticks


  • 1 large lemon
  • 2 drops food coloring
  • 2 drops liquid dish soap
  • tsp baking soda


  • Cut the bottom off of the lemon so it can stand upright, cut the top off of the lemon to expose the inside.  Place lemon upright on a baking pan lined with paper towels.
  • Take the popsicle stick and mash up the inside of the lemon to create juice and a little well, be sure not to go too far down in the lemon with mashing it up.  You don’t want to accidently poke through the bottom and have all of the lemon juice leak out.
  • Add in 2 drops of liquid dish soap and 2 drops of food coloring.  Stir a little bit to combine with the lemon juice.
  • Add in 1/8 teaspoon of baking soda and watch the lemon erupt.  You may need to stir a little to create mass amounts of bubbles.  When the bubbles calm down you can stir more to reactivate the baking soda or you can also add a little more baking soda.

You can keep this simple and just follow the directions above. Kids love a good surprise, but if you’d like to take it a step further, I have created a worksheet to go along with the experiment.

In all it took us about an hour to complete the experiment. We filled out the worksheet, discussed acids and bases, the pH scale, and for about 20 minutes the kiddos kept adding and repeating the eruption effect. We did this with friends as well, so this is an easy experiment to do with larger groups.

Do you have any science experiments you’ve done with your children, or students? Have you done this experiment before, or something similar? Hope y’all are having an amazing week.

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