Sample Answer Problem statement : What is the efect o diferent activity on the content o carbon dioxide in the air? Variables: MV: Diferent type o activity RV: Percentage o carbon dioxide in exhaled air. CV: Dration o activity!concentration o potassi" hydroxide!air sa"ple. Hypothesis: #he "ore vigoros the activity$ the higher the percentage o carbon dioxide. Apparatus: %&tbe$ basin$ delivery tbe$ boiling tbe$ and stop'atch Material: potassi" hydroxide soltion and 'ater Procedure:
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)ill a basin 'ith 'ater. Place a %&tbe in the 'ater. ,tart the stop'atch. nstrct the stdents to rn on the spot or / "intes. ""ediately$ collect a sa"ple o exhaled air sing the set p as sho'n in diagra" above. 0. #rap abot / c" o exhaled air in the ar" o %&tbe. 1. Place the %&tbe nder 'ater or / "intes to stabilise the te"peratre. 2. Measre nder 'ater the initial length o the air col"n and record in the table. 3. Re"ove the 'ater ro" the %&tbe ntil abot ( c" o 'ater re"ains or" the air col"n. (4.)ill + c" o potassi" hydroxide into the %&tbe. ((.Move the air col"n bac5 and orth to "ix the air 'ith potassi" hydroxide. (*.Place the %&tbe nder 'ater or / "intes to stabilise the te"peratre. (+.Measre nder 'ater the length o the air col"n and record in the table. (-.Repeat steps ( 6 (+ or t'o "ore diferent activities7 psh&ps and sitting.
