Floating and sinking bubbles

Bubbles of different sizes floating against a black background

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Make bubbles of carbon dioxide, hydrogen or methane in this demonstration exploring density, diffusion and solubility. Includes kit list and safety instructions.

In this experiment, students watch as bubbles of carbon dioxide – which sink in air – are created using dry ice. They then observe as hydrogen or methane is used to blow bubbles which float in air and can be ignited. Finally, mixtures of carbon dioxide and hydrogen can be used to blow bubbles which initially sink but eventually float.

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