What you will need

1/2 cup vinegar (white or apple cider vinegar work best)

1 cup of water

1 plastic Ziplock sandwich size bag (preferably a thin, cheap one)

1 tablespoon baking soda

Step One

Take the vinegar and 1 cup of water and put it in the Ziplock bag. Close the bag tightly and shake it gently. Note that your measurements don't need to be exact, but close.

Sept Two

Take the bag and put it in your sink or take it outside. If you are doing this experiment inside on a counter, make sure you have towels ready to clean up.

Step Three

Open the zip top just enough so that you can slide a measuring spoon in it. Take your baking soda and slip it in quickly. Immediately close the bag tightly.

Step Four

Observe. If nothing happens right away, gently shake the bag. As the baking soda and vinegar mix, gasses are formed and your bag should blow up and pop.

Why?

The baking soda is bicarbonate of soda. Bicarbonate of soda is a base and vinegar is an acid—which means that they are opposites. Combining these creates a chemical reaction that forms a gas. The gas builds up in the bag and then pops it. Although your preschooler may not understand the acid and base concepts they will likely understand the underlying preschool lesson--that two opposite chemicals can cause a reaction which can produce gas.

Variations

This experiment can be done in a larger Ziplock bag. Just double the ingredients. The experiment can also be done in a plastic grocery bag as long as the bag does not contain any holes and can be tied off quickly. Also, note that your measurements do not have to be exact. If you only have a little baking soda, the reaction will just be a bit smaller.

If you like this, also see Seven Easy Chemical Reactions for your Preschooler.

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Helpful Tips for Parents

• Integrate science into daily routines: cooking (chemistry), gardening (biology), building (physics), weather watching (meteorology). A science-rich home requires no special equipment.

• Science fear is learned, not innate. Preschoolers approach science with natural confidence — protect that confidence by keeping science joyful and low-stakes.

• The best science projects are the ones children generate themselves by noticing something in the world and asking why. Adult-imposed experiments are valuable; child-generated experiments are extraordinary.

• Document seasonal science observations over months and years. A child who tracks the same tree across four seasons has done longitudinal observational science — genuinely impressive.

Frequently Asked Questions

How do I build a child's science confidence when they get frustrated by unexpected results?

"Unexpected" is the word to use rather than "wrong" — in science, results that don't match predictions are the most interesting. "The result was different from what we expected — that means we discovered something! Let's figure out why." This reframe makes the unexpected result a success rather than a failure, because it produced a question worth investigating. Science confidence is built by treating all results as valid data, never as failure.

Are commercial science kits appropriate for preschoolers?

Commercial science kits designed for ages 4+ can be engaging starting points. Look for kits that use simple, safe materials and produce visually dramatic results (crystal growing kits, volcano kits, solar system model kits). Avoid kits with very small parts, complex safety requirements, or expected outcomes that are frustrating when not achieved. The best kits are those that leave children wanting to experiment further beyond the kit's instructions — look for kits with extension activities built in.

Related reading: See also our garden science guide and our weather science for more ideas on this topic.

🎓 Skills Your Child Will Develop

• 🔄 Flexible Thinking — When an experiment produces an unexpected result, children practice adapting their thinking — a form of cognitive flexibility that makes them more resilient learners across all subjects.
• 🏗️ Engineering Thinking — Testing structures, materials, and designs to see what works develops engineering intuition — the practical understanding of forces, materials, and design that underlies all physical construction and problem solving.
• 📝 Recording & Documentation — Drawing what they observe, recording measurements, and noting results gives children their first experience of scientific documentation — and connects science to literacy and numeracy in an authentic context.
• 🤔 Critical Thinking — Making a prediction, testing it, and explaining the result develops logical reasoning — the ability to move from observation to explanation that underlies all scientific, mathematical, and analytical disciplines.

Preschoolers love being in the kitchen. If they are not on a quest for treats, they may be there offering to help make the treats. The kitchen has so many neat gadgets and gizmos and wonderful smells that it is a very enticing place to get into trouble. But, it is also an amazing place for teaching your preschooler about science and nature.

There are a multitude of science experiments that can be done in the kitchen. A favorite experiment of many preschoolers is the baking soda bomb. It's a mild explosion but the reaction of baking soda and vinegar is fun to watch while it demonstrates beginning kitchen chemistry to your preschooler.