Experiment WS 3: 7.2A

Kowloon Tong School (Secondary Section)

F.2 Integrated Science

Experiment Worksheets 3

Name: _________________ (    )                                                               Date: __________________

Class: 2 _______

Experiment 7.2A: What is given out when a wooden splint burns? (P.16 - 17)

Objective: To study what is given out in burning.

Procedures:

1. Put a burning splint into a gas jar filled with oxygen. 2. When the burning splint goes out, take it out and immediately立即 cover the gas jar completely with the glass plate. 3. Touch接觸 the outside of the gas jar with your hand.   (a) What do you feel? My hand feels warm
4. (a) Observe the inner wall of the gas jar. What do you see on the inner wall of the gas jar? A layer of mist  (b) Let a piece of dry cobalt chloride paper touch the inner wall of the gas jar. Take it out immediately and cover the gas jar with the glass plate completely.      (i) What happens to the cobalt chloride paper? _______________________________________.
5.   Add 5 cm3 of hydrogencarbonate indicator into the gas jar. Cover the gas jar with the glass plate immediately. Shake the gas jar gently. Observe the colour of the indicator.    (a) What happens to the indicator?       It changes from red to yellow

Conclusion結論:

Ø   From the result of 3(a), it shows that heat energy is given out during burning

Ø   From the result of 4(a)(b), it shows that water vapour is given out during burning.

Ø   From the result of 5(a), it shows that carbon dioxide is given out during burning.

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.

Experiment WS 1: 7.1A &B

Kowloon Tong School (Secondary Section)

F.2 Integrated Science

Experiment Worksheets

Name: _________________ (    )                                                               Date: __________________

Class: 2 _______

Experiment 7.1A: Tests for oxygen and carbon dioxide

Objective:       To identify oxygen and carbon dioxide

Results:

Observation	Test results
	Oxygen	Carbon dioxide
1: colour of gas	colourless	colourless
2: smell of gas	odourless	odourless
3: change of burning splint	Burns more brightly	Goes out
4: change of glowing splint	Relights	Goes out
5: colour change of hydrogencarbonate indicator	No observable	Changes from red to
	changes	yellow
6: colour change of lime water	No observable	Changes from colourless
	changes	to milky

Discussion:

Ø   Oxygen can relight a glowing splints.

Ø   Carbon dioxide can turn lime water from colourless to milky.

Ø   Carbon dioxide can turn hydrogencarbonate indicator from red to yellow.

Experiment 7.1B: Tests for water and water vapour

Objective:       To carry out a simple test for water and water vapour.

Results:

Observation	Colour / Colour Change
	Dry	Wet
Cobalt chloride paper	blue	pink
Cobalt chloride paper in air	The colour changes from blue to pink

Discussion:

Ø   Cobalt chloride paper can be used to test for water.

Ø   From the result of dry cobalt chloride held in air for one to two minutes, we can conclude that air

contains water vapour.

WS 7.4 answer

7.4       How do green plants obtain energy?

i      Words to know:

	English term	Write the words again	Chinese term
1	Photosynthesis	Photosynthesis	光合作用
2	Raw material	Raw material	原料
3	Starch	Starch	澱粉
4	Chlorophyll	Chlorophyll	葉綠素
5	Iodine solution	Iodine solution	碘液

i      Fill in the blanks:

1        Green plants can make their own food by photosynthesis. The raw materials are
carbon dioxide obtained from the air and water obtained from the soil.

2        Light energy is required in photosynthesis. It is absorbed by Chlorophyll in green leaves and other green parts of the plants.

3        The food produced is usually stored in the form of starch. And oxygen is produced as a by-product that released into the air.

4        Write down the word equation of photosynthesis.

                                                             Light energy

Carbon dioxide  + water   ---------------------------------------à food   +    oxygen

                                                      Chlorophyll                         (starch)

5        Label the picture to show the process of photosynthesis. (Hints: Fig.7.12)

6        The test for starch using iodine solution is called iodine test.
A colour change from brown to dark blue shows the presence of starch.