Lesson 5 ·Class 9 · Respiration in Plants · Match Lab
Proving Respiration Happens
What each classic experiment actually shows.
Match each experiment to what it proves.
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Free play — tap an item on the left, then its partner on the right; each link tells you why. Switch to when you're ready to test yourself.
Ask what is being MEASURED in each: a volume change, a colour change, a temperature change, or a gas collected.
What this lesson covers
Challenges to clear
- Match every experiment to its conclusion.
- Connect the flask of boiled dead seeds to the reason it is set up at all.
The task
Match each experiment to what it proves.
What this lesson covers
- Germinating seeds in a flask with KOH, water level rising in the attached tube — Oxygen is used up during respiration (KOH absorbs the CO₂ released, so the volume drop measures oxygen consumed.)
- Air from a flask of germinating seeds bubbled through lime water — Carbon dioxide is given out (Lime water turns milky — the standard test for CO₂.)
- Germinating seeds in a vacuum flask, thermometer inserted — Heat is released during respiration (The temperature rises well above that of the boiled dead seeds used as control.)
- An identical flask of boiled, dead seeds set up alongside — Proves the effect is caused by living seeds, not by the apparatus (Without a control the experiment proves nothing.)
- Kuhne's fermentation tube with yeast and sugar solution — Anaerobic respiration produces carbon dioxide and alcohol (Gas collects in the closed limb and the mixture smells of alcohol.)
Hint
Ask what is being MEASURED in each: a volume change, a colour change, a temperature change, or a gas collected.