CIE IGCSE Biology: 复习笔记：11.1.3 Investigating the Differences in Inspired & Expired Air

• A simple experimental setup can be used to investigate the differences between inspired and expired air

The limewater test

• When we breathe in, the air is drawn through boiling tube A
• When we breathe out, the air is blown into boiling tube B
• Lime water is clear but becomes cloudy (or milky) when carbon dioxide is bubbled through it
• The lime water in boiling tube A will remain clear, but the limewater in boiling tube B will become cloudy
• This shows us that the percentage of carbon dioxide in exhaled air is higher than in inhaled air

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