Carbon Dioxide Experiments for Kids

Updated July 20, 2017

Carbon dioxide is a gas that occurs naturally in our environment. It has no taste, colour or odour. Humans inhale air and exhale carbon dioxide as a waste product. Plants use it to produce their own food. Carbon dioxide gas is forced into soft drinks to produce carbonation. The properties and easy availability of carbon dioxide gas make it a good candidate to use for kids' experiments.

Make Your Own Carbonated Lemon Drink

To make your own carbon dioxide for a fizzy drink, you need a lemon, a sharp knife, a glass measuring cup, 1 tsp baking soda, and 1/4-tsp sugar. Carefully cut the lemon in half widthways. Squeeze as much juice from the lemon halves as possible into the measuring cup. Add an equal amount of cold water, and stir in the sugar. Add the baking soda, and stir the mixture. Taste your carbonated lemon drink. The carbon dioxide formed through a chemical reaction between the lemon juice, an acid, and the baking soda, a base.

Inflating Balloons

This experiment uses carbon dioxide to inflate balloons. You need a medium-size balloon, 40ml of water, a glass soft drink bottle, plastic or glass funnel, long drinking straw, a lemon, a sharp knife, a small cup and 1 tsp.baking soda. Stretch out the balloon to make it easier to blow up. Cut the lemon in half widthways. Squeeze as much lemon juice into the cup as possible and set it aside. Pour the water through the funnel into the soda bottle. Add the baking soda, and stir thoroughly with the straw. Pour the lemon juice through the funnel into the soda bottle and quickly stretch the opening of the balloon over the opening of the soda bottle. The lemon juice and baking soda react chemically to produce carbon dioxide. The carbon dioxide gas rises out of the bottle, and inflates the balloon.

Carbon Dioxide Fire Extinguisher

Commercial fire extinguishers often use carbon dioxide to put out fires. You can see this at work by using a glass soft drink bottle, a plastic or glass funnel, a 3-by-5-inch index card, adhesive tape, 1 tbsp vinegar, 2 tbsp baking soda, a clean glass mayonnaise jar, a votive candle and a long-necked butane grill lighter. Pour the baking soda through the funnel into the soda bottle. Roll the index card into a tube, and tape it to hold the shape. Place the candle in the bottom of the jar, and ask an adult to help you light it with the lighter. Add the vinegar to the baking soda. "Pour" the carbon dioxide gas produced in the soda bottle through the index card tube into the jar. The candle flame needs oxygen from the air to burn. The carbon dioxide is heavier than air, and when it is poured into the jar, it sinks and pushes the air out of the jar. Without oxygen, the flame goes out.

Soda Geyser

This experiment makes a geyser using a 2-liter bottle of Diet Coke and 8 Mentos candies. Do this experiment outside in warm weather, and wear clothes that can get messy and wet. The reaction occurs rapidly once started, so be prepared to move away quickly. Unscrew and remove the soda bottle cap. Drop the Mentos into the soda quickly, and move away. Enjoy the eruption! The water molecules in the soda are strongly attracted to each other. The carbon dioxide gas is forced into the soda under high pressure when it is bottled, and the tight bonds of the water hold the carbon dioxide tightly in place. The water molecules resist the formation of new bubbles, and a lot of energy is needed to break the water's surface tension. Ingredients in the Mentos dissolve in the soda and break the surface tension, making it much easier for new bubbles to form. The tiny pores on the surface of the Mentos create ideal places for new carbon dioxide bubbles to form as soon as the come in contact with the soda. As the Mentos sink to the bottom of the soda bottle, they cause carbon dioxide to be released from all the soda with which they came in contact on the way down. The sudden increase in pressure due to the increased carbon dioxide and reduced surface tension of the water molecules in the soda cause all the soda to explosively push out of the soda bottle.

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About the Author

Annette Strauch has been a writer for more than 30 years. She has been a radio news journalist and announcer, movie reviewer for Family Movie Reviews Online, chiropractic assistant and medical writer. Strauch holds a Master of Arts in speech/broadcast journalism from Bob Jones University, where she also served on the faculty of the radio/TV department.