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Holiday Science: Fizzy Christmas Trees

This melting Christmas tree activity, inspired by Living Life & Learning, is all about a cool chemical reaction between the baking soda and the vinegar. This is a great experiment for kids that will create a love of science. Here's how to make your own fizzy melting Christmas trees...


  • 1 box baking soda
  • 1 cup water
  • 1 cup vinegar
  • Green food coloring
  • Sprinkles
  • Sequins
  • Large bowl
  • Rimmed cookie sheet
  • Rubber spatula (optional)
  • Pipette, eyedropper, small cup, or spray bottle
  • Measuring cup


  1. In the measuring cup, add water and green food coloring. You can use as much or as little food coloring as you’d like. It depends on how dark you’d like for your trees to be!
  2. Add box of baking soda to large bowl. 
  3. Slowly pour the water (with green food coloring) into the large bowl with baking soda. Use your hands (or rubber spatula) to mix the ingredients.
  4. Continue to add water until you’ve created a mixture that has the consistency of grainy toothpaste. Note:  you might not need all of the water.
  5. Mix in sequins and sprinkles with your hands (or a rubber spatula, if you’d prefer).
  6. Pour mixture onto cookie sheet.
  7. Use your hands to shape the mixture to look like evergreen trees. Note: if the mixture is too runny and your trees have trouble keeping their shape, mix in some more baking soda. If it’s too thick and dry, add a little water.
  8. With the pipette, eyedropper, small cup, or spray bottle, add vinegar to your trees.
  9. Watch your trees become a melty fizzy mess!

What’s going on?

As Living Life & Learning explains, there are two reactions at play here. The first is an acid-base reaction. When you mix acid (vinegar) and a base (sodium bicarbonate) they mix together to form two new chemicals—carbonic acid and sodium acetate.

The carbonic acid then begins to break down into water and carbon dioxide gas forms. That’s where all of the lovely bubbles come from.