Experiment WS 2: 7.1C & E

Kowloon Tong School (Secondary Section)

F.2 Integrated Science

Experiment Worksheets 2

Name: _________________ (    )                                                               Date: __________________

Class: 2 _______

Experiment 7.1C: Comparing比較 the oxygen and carbon dioxide content of breathed air未經呼吸的空氣 and unbreathed air呼出的空氣

Objective目標: To compare the oxygen and carbon dioxide content of breathed air and unbreathed air.

B. Comparing the oxygen content

	Breathed air	Unbreathed air
Time taken for burning splint to go out (s)	(longer time)	(shorter time)

C. Comparing the carbon dioxide content

	Breathed air	Unbreathed air
Colour of hydrogencarbonate indicator after shaking	yellow	red

Conclusion結論:

Ø   Breathed air contains less oxygen than unbreathed air.

Ø   Breathed air contains more carbon dioxide than unbreathed air

Experiment 7.1E: Compare the water vapour content of breathed air and unbreathed air

Objective:       To compare the water content of breathed air and unbreathed air.

Results:

	Under breathing	Without breathing沒有呼吸
Colour change of the cobalt chloride paper	changes from blue to pink	No change / changes to pink more slowly

Conclusion:

Ø   Breathed air contains more water vapour水蒸汽 than unbreathed air.