Summer School with Live Science: Lemon volcanoes - Livescience.com

In this week's installment, Live Science producer, Diana Whitcroft, will demonstrate the reaction between sodium bicarbonate (baking soda) and citric acid (lemon juice, in this case).

Then, cut off the top of the lemon, exposing the inside pulp and juice.

Using your popsicle stick, mash the inside of the lemon so that the "meat" or fleshy interior is completely pushed down and the lemon is filled with mostly juice.

The amount of food coloring you use is dependent on the size of your lemon and how much juice it yields.

Small lemons with very little juice: 2-3 drops.

Large lemons with a lot of juice: 4-5 drops.

Using your spoon, sprinkle into your lemon a few teaspoons of baking soda.

Again, depending on the size of your lemon, you'll need to adjust the amount!

Small lemons with little juice: 2-3 tsp.

Right away, you should see bubbling and fizzing, but it is likely that you'll need to use your spoon or popsicle stick to better mix the juice and baking soda!

When the baking soda was added to the lemon juice, it bubbled and foamed.

That is because when sodium bicarbonate (baking soda) and citric acid (lemon juice) are combined, they react by forming carbon dioxide gas as well as a chemical compound called sodium citrate.