Teacher ideas: testing for carbon dioxide

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What you will need

Provide each group with 20 millilitres of vinegar, a tablespoon of sodium bicarbonate, a film canister and lid, or a similar container with non-screw, tight-fitting lid.

Alternatively demonstrate the experiment to the class.

Teaching focus

Use a simple chemical reaction to provide an example of how carbon dioxide is produced by combining two common household substances. Use the activity to discuss physical and chemical processes that release carbon dioxide into the atmosphere, for example breathing, mixing certain chemicals together and burning fossil fuels.

What to do

Place a tablespoon of sodium bicarbonate into the film canister. Add 20 millilitres of vinegar and immediately attach the lid. Sit the film canister on its lid. Students carefully observe what happens.

Note the canister will be under pressure from the build-up of carbon dioxide produced by the chemical reaction. The canister should be forced upwards as the gases build and the lid is forced open.

Predict, observe, explain

Prior to observing the addition of vinegar, ask students to predict what they think will happen when the two substances are combined and placed in the canister with the lid tightly closed.

Students describe their observations, for example what they heard and saw. They explain their observations and compare to their prediction.

Have students draw a diagram of the activity and write down their observations.

Pose the question: What is the gas that was released?

Review the use chemical formulas in an equation to show the chemical reaction that resulted in the production of carbon dioxide. Were any other chemicals made in the reaction?

Further inquiry

Prompt students to think about carbon dioxide as part of the natural environment and as a source of ghgs by asking questions such as:

  1. Find out about respiration and how living things produce carbon dioxide. Plants photosynthesise and produce their own food in the form of sugars in a process that requires carbon dioxide. Plants also undergo respiration. Have students write a brief report and include labelled diagrams.
  2. Use a candle as an example to explain how carbon dioxide is produced when a substances burns (combustion).
  3. Find out how cement is manufactured. How is concrete made? Use chemical formulas and equations to describe the process. How does cement production contribute to climate change?